tag:blogger.com,1999:blog-85702203380765530892024-02-27T08:46:05.575-08:00Botany Professor
Essays, botanical travelogues, and other resources provided for students, instructors and anyone else seeking a deeper understanding of the nature of plants. Proceed below for recent posts or go to the Table of Contents (in the column to the right) for an organized list of topics.Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.comBlogger127125tag:blogger.com,1999:blog-8570220338076553089.post-1453505826473830872023-09-25T14:19:00.004-07:002023-09-26T13:37:48.992-07:00Cactus? Look again!<p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiatKLNsbm7lsGGj5EomS957KI8yc2Mm5NsB6xVONVREyAm2VskRGP8hCcQvwqC5s2nobseAgKtPSFIBYarCjfDHJqWiOrpQda-4c4gGOy-1X6frnSG-lOtE4xNUJnr7qIx8-uq5KLZEybnahdfB9ZoNFjZ98HwPr2uDRvSuEpUHIjtVSzGuY2BhgpBIsgo/s786/14098%20Aloe%20erinacea.JPG" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="786" data-original-width="527" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiatKLNsbm7lsGGj5EomS957KI8yc2Mm5NsB6xVONVREyAm2VskRGP8hCcQvwqC5s2nobseAgKtPSFIBYarCjfDHJqWiOrpQda-4c4gGOy-1X6frnSG-lOtE4xNUJnr7qIx8-uq5KLZEybnahdfB9ZoNFjZ98HwPr2uDRvSuEpUHIjtVSzGuY2BhgpBIsgo/w269-h400/14098%20Aloe%20erinacea.JPG" width="269" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><i>Aloe erinacea</i> superficially resembles a <br />cactus, but closer examination reveals <br />that the plant consists of closely-spaced,<br />spirally-arranged succulent leaves with <br />spines along the edges. In cacti, leaves <br />are done away with altogether, or adapted<br />as spines.</td></tr></tbody></table> The picture at the right is a member of the genus <i>Aloe</i>. We all know the most common member of this genus, <i>Aloe vera</i>, grown as a garden ornamental, as a source of skin ointment, or for its edible leaves. The species pictured, <i>Aloe erinacea</i>, with its compact, rounded overall shape and prominent spines, superficially resembles a small barrel cactus. Aloes and cacti are both succulent plants adapted to survive arid conditions by storing water in their tissues. In cacti, it is the stems that are modified to store water, while in aloes, it is their leaves. A careful look at this plant reveals that it does in fact consist of a compact series of spirally arranged leaves. <div><br /></div><div>When unrelated organisms come to resemble each other, it is an example of <b>convergent evolution</b> - similarity due to common adaptation, but from very different ancestors.<p></p><p>I've spoken of this a number of times on this site, as succulents in general are a spectacular example of convergent evolution and the all-important process of <b>adaptation. </b>I've been retired for a number of years, but if were to go back into the biology classroom again today, I would walk up to the front and write <b>ADAPTATION</b> on the board (or powerpoint screen!). I would then proceed to show how everything we see in organisms is a result of this process, which unites genetics, ecology, evolution, and systematics.</p><p>Cacti and aloes have very different evolutionary histories leading to their convergence. In this post, I want to emphasize the <b>historical </b>dimension of adaptation. The current functional features of a plant have histories of gradual change, sometimes adding or improving functionality, sometimes changing the function altogether. Leaves themselves underwent extensive series of adaptations in early plants just to become the flat, efficient light-gathering antennae that we know today, and similar series of adaptations happened <a href="http://botanyprofessor.blogspot.com/2013/11/a-leaf-by-any-other-name.html">multiple times</a> in different groups of plants. the very leafiness of leaves itself is convergent in true mosses, clubmosses, ferns, different groups of seed plants.</p><p> In various lineages of plants, leaves were further modified into the parts of gymnosperm cones, the parts of the <a href="https://botanyprofessor.blogspot.com/2020/05/the-leafy-origins-of-sepals.html">flower</a> and other reproductive structures. Leaves have also been modified through adaptation into grasping tendrils, sticky insect-catching traps, and other specialized structures. In cacti, leaves disappeared, or were converted into spines, as the stems adapted simultaneously for photosynthesis and water-storage. In aloes, leaves retained their photosynthetic function, while adding water storage.</p><p>Both cacti and aloes thus came from "normal" plants adapted for less arid conditions. Among the nearest non-succulent relatives of cacti are carnations, and of aloes they are daylilies, asparagus, and amaryllis. Cacti are eudicots, which typically have prominent stem systems and relatively small leaves. Aloes are monocots, which typically have condensed, inconspicuous, and mostly underground stems, but prominent, elongate leaves. It was "easier" for cacti to adapt their already exposed stems for water storage, but for aloes it was easier to add that function to their leaves, than to redesign their underground stems. So in adapting to new conditions, organisms <i>modify what they already have</i>, in the simplest way ("along the lines of <a href="http://botanyprofessor.blogspot.com/2014/07/g-l-stebbins-and-process-of-adaptive.html">least resistance</a>").</p><p>So in considering the process of adaptation, we must keep in mind that organisms adapt to new or changing conditions by modifying <b>pre-existing</b> structures. Developing new organs from scratch happens rarely, if ever. In plants, stems and leaves have been the most plastic of organs, forming a wide variety of distinctive adaptive organs.</p><p>For some zoological examples, take the wings of birds. These highly specialized flight organs evolved from the front legs of their non-flying ancestors, radically changing their function. It happened separately in flying pterosaurs and in bats, using arm and hand bones differently. It did not end there with the birds, for wings went through another transformation in penguins, from flying organs to swimming organs. In snakes, legs disappeared altogether or remained as a set of tiny useless bones buried within their muscles, what we refer to as <b>vestigial</b> organs. The same thing happened in whales, where the front legs were modified into flippers, while the hind legs were reduced to buried vestigial structures. So one possible endpoint for a history of adaptations is to disappear!</p><p>Studying the history of adaptations in particular animals, or particular organs, is one of the most fascinating areas of biology, helping us understand the strange bedfellows resulting in modern classification (carnations and cacti, asparagus and aloes!), as well as the process of adaptation and the ecology of organisms. Proposed evolutionary scenarios must always include a plausible evolutionary (i.e. adaptive) history of how they came to be. </p><p>The aloes and some closely related genera, incidentally provide another opportunity for a theme and variations expedition like I did with the Amaryllis family a little while ago. These leafy succulents are native primarily to Africa, and here are some photos from my collection:</p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhqDocCbJJ2ihxi363MdheBz31FKsGNRVaXeeCI_lCmhxsu3QDYSss5fEwmpxAkf8DkTrVm22jnaN6JUTiCNFPje087UdLXQCrxeUxgWT-oaYKDqRJngZAaOqwCxQswGXFWCogEb98ZAoDB5d0mYjHwW9uFaLlHSbnBBHoyyMUWNPuydz9uDAxjmDOnAP78/s1544/2005-03%20USFBG%20Aloe%20(2).JPG" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1544" data-original-width="1024" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhqDocCbJJ2ihxi363MdheBz31FKsGNRVaXeeCI_lCmhxsu3QDYSss5fEwmpxAkf8DkTrVm22jnaN6JUTiCNFPje087UdLXQCrxeUxgWT-oaYKDqRJngZAaOqwCxQswGXFWCogEb98ZAoDB5d0mYjHwW9uFaLlHSbnBBHoyyMUWNPuydz9uDAxjmDOnAP78/s320/2005-03%20USFBG%20Aloe%20(2).JPG" width="212" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Close-up of an unidentified Aloe<br />showing the emergence of new<br />leaves in the center.</td></tr></tbody></table><br /><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSitPi3tOQU4D4jvNkvqyETjkWsNOjEEXjWGyp93eSRegECoFt82UhWmkiSMxUpks0o2CC5UylNrBjTISgAw0cqea2s_U5ztQFLFhHSLS307i_29uoBd8hi08xdsbYc0HZAnDnxxdRFZzo1swZPwlLI4krPsVebkzanLoX462XM8kH665kkKexjNPdRHFz/s3008/13612%20Aloe%20plicatilis.JPG" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3008" data-original-width="2000" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjSitPi3tOQU4D4jvNkvqyETjkWsNOjEEXjWGyp93eSRegECoFt82UhWmkiSMxUpks0o2CC5UylNrBjTISgAw0cqea2s_U5ztQFLFhHSLS307i_29uoBd8hi08xdsbYc0HZAnDnxxdRFZzo1swZPwlLI4krPsVebkzanLoX462XM8kH665kkKexjNPdRHFz/w266-h400/13612%20Aloe%20plicatilis.JPG" width="266" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><i>Aloe (</i>or<i> Kumara) plicatilis </i>is <br />unusual in having its leaves <br />arranged in a single plane.</td></tr></tbody></table><br /><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEij1WF0t67TKvcR8lv1JrceHGRMXDtO9aVogz4ucLdQuwCdqvDKjeUDjQqVY0SARP4Y7iVy9C4iiqtj1W1FRNI5l0GyATB7BHeY2Ox8wFALA1SEpldXkN1TFI292FGgmn6Ur6USA3XTHVnQXhBrxS8YxEfEonqDPYfBEO6YYZxNdifpdlrWmgC98NILA3OC/s2245/13839%20Aloe%20variegata.JPG" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2245" data-original-width="1849" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEij1WF0t67TKvcR8lv1JrceHGRMXDtO9aVogz4ucLdQuwCdqvDKjeUDjQqVY0SARP4Y7iVy9C4iiqtj1W1FRNI5l0GyATB7BHeY2Ox8wFALA1SEpldXkN1TFI292FGgmn6Ur6USA3XTHVnQXhBrxS8YxEfEonqDPYfBEO6YYZxNdifpdlrWmgC98NILA3OC/s320/13839%20Aloe%20variegata.JPG" width="264" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><i>Aloe (</i>or<i> Gonialoe) variegata<br /><br /></i></td></tr></tbody></table><br /><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikXIcgbdwuZOj12NJWwRlsZFGKONTjg2uayU3g042V9wHmSbjC4l5otMPaFU950KS-u7rWsN52_URD9OpgrIgtkxJK22-JmofpwAa7XWSr_jfk7gu_qN7xMR-2DG2gj0YryvRBu5GxJKH_CYMe9EHvDx3EXcXwyZgy2ysJgT_Ckla_3CQeHCsZj7n3IBMF/s2819/14097%20Aloe%20pitchifolia.JPG" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2819" data-original-width="1946" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikXIcgbdwuZOj12NJWwRlsZFGKONTjg2uayU3g042V9wHmSbjC4l5otMPaFU950KS-u7rWsN52_URD9OpgrIgtkxJK22-JmofpwAa7XWSr_jfk7gu_qN7xMR-2DG2gj0YryvRBu5GxJKH_CYMe9EHvDx3EXcXwyZgy2ysJgT_Ckla_3CQeHCsZj7n3IBMF/s320/14097%20Aloe%20pitchifolia.JPG" width="221" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><i>Aloe pictifolia</i></td></tr></tbody></table><br /><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFyOnVFQyihhFItwBMrp6DmP0KJc3T4CBCtlKTq9F2yG7LDYfOasn7_ZhXKAG8hdOvWqgFjFiKB3bAptooUzcT7EfXmFdhkDZX9mWTHiGRV_ZqN8Y6saYCILDOxXEdxpN5FXQQkc2JEvG8tUVoF2QD8n1Abw5bXl4njxkl5kTgQYYkCJh6fuZlRbrAu6af/s1792/14132%20Aloe%20dichotoma.JPG" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1792" data-original-width="1168" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFyOnVFQyihhFItwBMrp6DmP0KJc3T4CBCtlKTq9F2yG7LDYfOasn7_ZhXKAG8hdOvWqgFjFiKB3bAptooUzcT7EfXmFdhkDZX9mWTHiGRV_ZqN8Y6saYCILDOxXEdxpN5FXQQkc2JEvG8tUVoF2QD8n1Abw5bXl4njxkl5kTgQYYkCJh6fuZlRbrAu6af/w418-h640/14132%20Aloe%20dichotoma.JPG" width="418" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><i>Aloe dichotoma </i>is a rare example of a monocot that becomes a tree <br />through an unusual type of secondary growth.</td></tr></tbody></table><br /><p><br /></p></div>Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-57913113225984263292023-04-03T13:31:00.004-07:002023-04-03T13:31:55.292-07:00The difference between blackberries and mulberries and why it matters<p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi85UV5rkVQLo3LihWdfnA1jtubQ55o6vj3Sx2E-qWLjgMjX5NV8RLH9ny1364VhNkniWOa0Ms4-I0dXKDOEufOkvZxlX6QQZ7iu7edLbaBlQJv6l8VIAw4fGVKT89u-H3PO26QGMRVDwY7GlWPWpQN9PEmsjkJvQYCeBidGRwiUP7l0LMbnSMun83xKA/s4000/20230402_080605.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi85UV5rkVQLo3LihWdfnA1jtubQ55o6vj3Sx2E-qWLjgMjX5NV8RLH9ny1364VhNkniWOa0Ms4-I0dXKDOEufOkvZxlX6QQZ7iu7edLbaBlQJv6l8VIAw4fGVKT89u-H3PO26QGMRVDwY7GlWPWpQN9PEmsjkJvQYCeBidGRwiUP7l0LMbnSMun83xKA/s320/20230402_080605.jpg" width="320" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Blackberries grow on prickly vines or brambles, <br />and are members of the Rose Family (Rosaceae).</td></tr></tbody></table> As I was picking mulberries from a tree in my back yard the other day, I was reminded of the similarity between blackberries and mulberries. They are strikingly similar in appearance. <div><br /></div><div>Like most dark fruits, they are both rich in nutrients and protective phytochemicals. For the consumer, the primary differences are the somewhat milder, less sweet flavor, and the annoying little green stems of of mulberries. Depending on the climate, one or the other may be easier to grow, and fresh blackberries are generally more widely available in stores. Dried mulberries, however, are becoming increasingly popular and more available. Beyond all that, it's a matter of taste.<p></p><p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlgx9oVxKDmKQNyc3_BiAC6IdNt90NcyVdbPJaC0dMWJRoLiOxJNracjPDNvA2jCtHd_kvpVZ0ITD08p320Tg0IG1NDc-bt16QdI9QaQJVlastFhAc3niDuA1yEaSpGPkKiGpdsVGTilLduOoGgvPJPO0zONfdwPDQqlzV7g4fA9UA7dlIYeNTjoL_0Q/s4000/20230402_080437.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhlgx9oVxKDmKQNyc3_BiAC6IdNt90NcyVdbPJaC0dMWJRoLiOxJNracjPDNvA2jCtHd_kvpVZ0ITD08p320Tg0IG1NDc-bt16QdI9QaQJVlastFhAc3niDuA1yEaSpGPkKiGpdsVGTilLduOoGgvPJPO0zONfdwPDQqlzV7g4fA9UA7dlIYeNTjoL_0Q/s320/20230402_080437.jpg" width="240" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Mulberries grow on trees, and are <br />members of the Mulberry Family <br />(Moraceae).</td></tr></tbody></table><br />In terms of the teaching of botany and evolution, however, the similarities and differences between the two berries tell a powerful story. Though they function the same way in natural fruit dispersal, they are not related at all. Blackberries are members of the the very fruitful family, Rosaceae, which includes raspberries, strawberries, plums, cherries, peaches, apricots, apples, pears, rose hips and many more. Mulberries, on the other hand are members of the Moraceae, which includes figs, breadfruit, and rubber trees. <p></p><p>The structures of the two fruits are quite different. Blackberries are <b>aggregate fruits</b>, which means that the cluster of drupelets derive from a cone of separate carpels belonging to a single flower. Mulberries on the other hand are technically <b>infructescences</b>, or <b>compound fruits,</b> similar to pineapples. Each drupelet forms from its own tiny flower. So there are fundamental developmental differences that lead to the similar looking fruits.</p><p>This might seem like a geeky bit of botanical trivia that would quickly make dinner guests fall asleep, but in the classroom, however, it illustrates some of the most central phenomena of evolution: <b>adaptation</b>, <b>adaptive radiation</b>, and <b>convergent evolution</b>.</p><p>These fruits, first of all, are <b>adapted</b> for dispersal by animals, primarily birds, though I have had to keep an eye out for hungry black bears as well while picking berries along roadsides in Washington State. Both go through green and red phases before turning black at ripening. This primes the animals for the coming feast. The berries are sweet, juicy, and flavorful. The animals gobble down the fruits, and the digestive process strips away the juicy tissues, leaving the tiny seeds to pass through the alimentary canal. The animals tend to move about after feeding, leaving seeds in their feces. (See also "<a href="https://botanyprofessor.blogspot.com/2015/10/what-is-adaptation.html" target="_blank">What is an Adaptation?</a>)</p><p>The different kinds of fruit to be found in the Rose Family are an example of <b>adaptive radiation </b>- the evolution of a variety of descendant species from a common ancestor<b>. </b>As the descendants of the common ancestor began spreading into new habitats and new geographic areas, they adapted to local conditions, including local fruit dispersers. </p><p>As other families went through their own adaptive radiations, some descendants encountered the same opportunity for dispersal, and developed similar physical characteristics, but with tell-tale differences in underlying structure. This is <b>convergent evolution -</b> the development of very similar adaptations from unrelated ancestors. The ancestors of the Rose Family happened to have flowers with multiple separate carpels, and so easily evolved into aggregate fruits, while the ancestors of the Mulberry Family had tiny flowers with just one carpel in each, so a similar fruit was most easily developed by grouping the fruits of many flowers together. I have posted earlier about evolution of cactus-like members in unrelated families, along with numerous examples of convergent evolution in animals. (See "<a href="https://botanyprofessor.blogspot.com/2018/11/of-cacti-and-humans-are-certain-life.html" target="_blank">Of cacti and humans – are certain life forms inevitable</a>?"</p></div>Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-89925965710609487392022-12-25T08:41:00.001-08:002022-12-25T08:41:14.935-08:00Why do coconut palms lean?<p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_uRbUr9hJxnFs1OB7kN0yIcIjxItah2Sy8OxF3H_B4I3RR_7II59XoRuot-7yQxGnr5gPOLX7aAbsGtluEvOjC5zD-2wEA66Ry9w__03AdgOKEJWg3Lj5lGfbKSuAIuJ9U0w6RbL6mfVhJ8eSMQvr-XWJK2SLwmPz7C879FiZ23xwz_l0WmyPRTWLjg/s3000/20221206_151739.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2952" data-original-width="3000" height="315" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_uRbUr9hJxnFs1OB7kN0yIcIjxItah2Sy8OxF3H_B4I3RR_7II59XoRuot-7yQxGnr5gPOLX7aAbsGtluEvOjC5zD-2wEA66Ry9w__03AdgOKEJWg3Lj5lGfbKSuAIuJ9U0w6RbL6mfVhJ8eSMQvr-XWJK2SLwmPz7C879FiZ23xwz_l0WmyPRTWLjg/s320/20221206_151739.jpg" width="320" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Coconut palms commonly grow along tropical coastlines<br />in a zone of salt-tolerant vegetation, but not directly in <br />saltwater. Coconuts may fall onto the beach and be carried <br />away by high tides, but not usually directly into the water.</span></td></tr></tbody></table> Coconut palms have a distinctive, arching growth form, which is somewhat unusual among palms. Most solitary, tree-like palms grow straight upward rather rigidly. The reason for the coconut palm's graceful arch has led to much speculation online, some of it rather goofy, such as that they lean out over the shoreline in order to drop their coconuts into the water for dispersal. Slightly more plausible is that they lean toward the light, or that they are bent by the coastal breezes. <p></p><p>While these factors may contribute somewhat to the ultimate shape of the mature palms, I'd like to point to a more fundamental factor: the phase of development that all palms go through after germination called <b>establishment growth</b>. This is something peculiar to tree-like monocots, which have neither a taproot system nor layered <b>secondary growth</b>. In dicotyledonous trees, stem thickness increases gradually throughout the plant, and the root system branches to keep up with it. (<i><a href="http://botanyprofessor.blogspot.com/2012/03/root-of-root-problem.html" target="_blank">See The Root of the Root Problem</a></i>)</p><p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgKgnbRAU98zCpgYzrmMlp6c19g7fZEUDeHfBlAGENwpRuyaM2-f3d_NgjJO6lh_jI2QzkofH63RcBQz_sXZvK7Ksa0SVW4GZtF25fWc75fJFkaf6hr3fBh0aZb2y4meUnnQdMS9S1AuTO9IL8LNVqYTZV0jCyEyy_xv-o72-CiauG9jLfDTr5-HB7PNQ/s4000/20221207_142359.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgKgnbRAU98zCpgYzrmMlp6c19g7fZEUDeHfBlAGENwpRuyaM2-f3d_NgjJO6lh_jI2QzkofH63RcBQz_sXZvK7Ksa0SVW4GZtF25fWc75fJFkaf6hr3fBh0aZb2y4meUnnQdMS9S1AuTO9IL8LNVqYTZV0jCyEyy_xv-o72-CiauG9jLfDTr5-HB7PNQ/s320/20221207_142359.jpg" width="320" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">While coconut palms may appear to all lean toward<br />the ocean (to the left in this picture), they in fact may lean <br />inland as well, at least at the beginning. Only a few <br />at the far upper left of this photo are actually leaning <br />toward the ocean. Note that the bases of the stems emerge from <br />the ground at a distinct angle. This is the result of the<br />early phase of horizontal establishment growth. </span></td></tr></tbody></table><br /><br /><div>Most monocots keep their main stems underground as rhizomes, corms, or bulbs, and produce adventitious roots. Leafy shoots and/or flower stalks typically arise directly from these underground stems, and die back after their reproductive cycle. Becoming trees, as in palms, screwpines (<i>Pandanus</i>) or traveler's "palms" (<i>Ravenala</i>), was an evolutionary afterthought, for which new ways to develop trunk thickness and a sufficient root base had to be invented. (See also <i><a href="http://botanyprofessor.blogspot.com/2012/05/invention-and-reinvention-of-trees.html" target="_blank">The Invention and Reinvention of Trees</a></i>.)</div><div><br /></div><div>Monocot trees do this by developing their full stem thickness, along with a mass of permanent adventitious roots, at, below, or close to the ground before beginning their vertical growth. The trunk base can widen only by extending more roots into the soil. This is what we call establishment growth. </div><div><p></p><div><br /></div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiulwwNSYGj95-FeVUM0ZFqCrO_rULdJHE2hpWzAl5nUy4Uz4VtTB7MjEsDpe5i80clGhq5nw-Kgwq6PKFNjE8UPWqTMgHz5v6kZxCiKeeO_EzhlYwzBFVjgNaRQAQItxupvdOpSfLToPgtJLJBEGtGOIipGxjjWz5vCOiJhuqtk97IOkJwinCuEFxpvA/s393/Capture.JPG" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="393" data-original-width="374" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiulwwNSYGj95-FeVUM0ZFqCrO_rULdJHE2hpWzAl5nUy4Uz4VtTB7MjEsDpe5i80clGhq5nw-Kgwq6PKFNjE8UPWqTMgHz5v6kZxCiKeeO_EzhlYwzBFVjgNaRQAQItxupvdOpSfLToPgtJLJBEGtGOIipGxjjWz5vCOiJhuqtk97IOkJwinCuEFxpvA/w191-h200/Capture.JPG" width="191" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;"><span>The underground stem of a cabbage <br />palmetto </span><span>during establishment growth <br />is shaped </span><span>roughly like a saxophone, with </span><br /><span>the mouthpiece representing the seed, <br />and the </span><span>opening of the bell <br />representing the ever-widening shoot <br />apex. You have to imagine </span><span>roots <br />sprouting along the body of the <br />saxophone, </span><span>and leaves emerging from the <br />open end of the bell.</span><span> </span><br /><span>Drawing from Drawforkids.com.</span></span></td></tr></tbody></table><div>There are several ways to do this. In cabbage palms (<i>Sabal spp.</i>), for example, the shoot apex first grows downward into the soil, sending up its juvenile leaves and sprouting adventitious roots as it goes. The stem tip gradually widens and then turns upward. The overall shape of the stem at this stage resembles a saxophone. By the time the shoot apex (stem tip) reaches the soil line, it is as wide as it is going to get, and begins forming a an upright trunk. This takes some 25 years for a Sabal palm.</div><div><br /></div><div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0nEfoLYNBwVVk_e7kLnLKts-_pE0_33FlmUO3RhncA0f-SrGyf_q81qcZN13OX5n0JTXCvKuWmXOv_Mh0AOQl1Z8bedKoRTxbtnBEPCb4eEU4r-m0ZfWUSUMHrwrBHX3oAI5kwAiOS3OGSAr-9LZevJwGNKj-eX4uOAPxmBpN2Ed56L7n_uLCneyfXQ/s4000/20221212_093200.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0nEfoLYNBwVVk_e7kLnLKts-_pE0_33FlmUO3RhncA0f-SrGyf_q81qcZN13OX5n0JTXCvKuWmXOv_Mh0AOQl1Z8bedKoRTxbtnBEPCb4eEU4r-m0ZfWUSUMHrwrBHX3oAI5kwAiOS3OGSAr-9LZevJwGNKj-eX4uOAPxmBpN2Ed56L7n_uLCneyfXQ/s320/20221212_093200.jpg" width="240" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">The production of s series of aerial stilt <br />roots allows this palm to increase the <br />thickness of its stem while growing upward.</span></td></tr></tbody></table>Other palms, as well as screw pines, begin growing upward immediately out of the seed, as very slender stems that widen as they grow upwards and produce adventitious roots that remain for the life of the plant in the form of <b>stilt roots</b>. </div><div><br /></div><div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgWuh_eeXGLlSaAg7hKr4HiNjcyHApqjAu78Zp-vVEOmUcF61eJ8XXeWjol39PoQRSm64De-U4jd1vWoK48EfohJ05nvsUGtsjGCpfQoa_KZkhkk06AeZNM8wgyQstmdznKBydpJmmmkjqbCHKFCOy0qj86EOezVsmX5zqS2X_BEDHeCR1zrz_vxzs0g/s640/xoxonut%20seedling%20Wikipedia.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="480" data-original-width="640" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgWuh_eeXGLlSaAg7hKr4HiNjcyHApqjAu78Zp-vVEOmUcF61eJ8XXeWjol39PoQRSm64De-U4jd1vWoK48EfohJ05nvsUGtsjGCpfQoa_KZkhkk06AeZNM8wgyQstmdznKBydpJmmmkjqbCHKFCOy0qj86EOezVsmX5zqS2X_BEDHeCR1zrz_vxzs0g/s320/xoxonut%20seedling%20Wikipedia.jpg" width="320" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">The horizontal establishment growth of the coconut<br />palm stem will proceed to the right in this example.<br />Photo by Vencel, CC attribution 3.0.<i style="background-color: #f7f8ff; color: #202122; font-family: sans-serif; margin-left: auto; margin-right: auto;"> </i></span></td></tr></tbody></table><br />It appears that the coconut palm follows a third model by establishing its basal thickness along with a mass of adventitious roots, through a period of condensed horizontal growth, with the lower side of the trunk remaining in contact with the soil. Once it achieves full thickness, the trunk gradually curves upward to achieve a more-or-less upright growth, though it often continues to lean. Since a coconut seedling sprouts out of one end of the coconut, the direction of the horizontal growth phase and the eventual upward curve, will depend on which way the coconut is facing when it sprouts - not so much for any functional reason. </div><div><br /></div><div>This is my hypothesis anyway. Those of you who have grown coconut palms from seed can perhaps verify or correct it. </div></div>Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-85105744030503965392022-11-21T14:07:00.003-08:002022-11-21T14:07:56.076-08:00The major breakthroughs of plant evolution<p> As plant life evolved, several major breakthroughs allowed them to greatly expand their footprint across the globe. These breakthroughs were major macroevolutionary shifts brought about by a series of small microevolutionary adaptations. <a href="http://botanyprofessor.blogspot.com/2011/10/essential-characteristics-of-plants.html" target="_blank"><i>The essential characteristics of Plants</i></a> are each associated with one or more of these major breakthroughs. Such events are described in more detail in <i><a href="http://botanyprofessor.blogspot.com/2015/02/plant-life-brief-history.html" target="_blank">Plant Life: a Brief History</a>,</i> I present here a brief synopsis of those major events:</p><p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj3_nNLecCBowrULqsNK6yn31E1694ULOraeX-JRRnZ8TeMR-6FQRnaCl9haTly_RO8cq7CMjYRixVaya7iH8GThmd7_JukJ3QpCG8B1lf7dN3YgvW_3qLoH0n_9LzWN_944nbp-wUt2q-w1H9jRoMLX5Id6aO3_DFiugwQcO4NtCfqF-ke-wUqRjOepQ/s967/967px-Stromatolites_in_Sharkbay.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="720" data-original-width="967" height="146" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj3_nNLecCBowrULqsNK6yn31E1694ULOraeX-JRRnZ8TeMR-6FQRnaCl9haTly_RO8cq7CMjYRixVaya7iH8GThmd7_JukJ3QpCG8B1lf7dN3YgvW_3qLoH0n_9LzWN_944nbp-wUt2q-w1H9jRoMLX5Id6aO3_DFiugwQcO4NtCfqF-ke-wUqRjOepQ/w196-h146/967px-Stromatolites_in_Sharkbay.jpg" width="196" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">The earliest known fossil cyanobacteria </span><br /><span style="font-size: x-small;">formed layered colonies that slowly </span><br /><span style="font-size: x-small;">built pillar-like formations called</span><br /><span style="font-size: x-small;"> stromatolites, like these from </span><br /><span style="font-size: x-small;">present-day Australia. Photo by Paul </span><br /><span style="font-size: x-small;">Harrison, </span><a class="mw-mmv-license" href="http://creativecommons.org/licenses/by-sa/3.0/" style="background: none rgb(248, 249, 250); color: #0645ad; font-family: sans-serif; outline-color: rgb(51, 102, 204); text-align: right;" target="_blank"><span style="font-size: xx-small;">CC BY-SA 3.0</span></a></td></tr></tbody></table>1.<b> Origin of <i><a href="http://botanyprofessor.blogspot.com/2012/12/the-first-plants.html" target="_blank">photosynthesi</a>s </i></b>- this central plant process not only marked the beginning of plant life, but also opened up a vast new energy supply to all life on earth and providing the oxygen supply that allowed for complex food webs and distinctive ecosystems. Though seemingly a long, complex process, different parts of photosynthesis evolved separately in more ancient bacteria and were brought together through <b>horizontal gene transfer</b>. <b>Carbon-fixation</b> or the <b>Calvin Cycle</b>, had its roots in earlier <b>chemoautotrophic </b>organisms, where it was driven, not by sunlight, but by energy captured from sulfur and other compounds bubbling up from undersea volcanic vents. The ability to capture sunlight evolved among other bacteria, likely producing only ATP as its product. When coupled with the carbon-fixation process ,simple forms of photosynthesis came into being. The first organisms capable of modern photosynthesis, which releases oxygen as a byproduct, were the <b><a href="https://botanyprofessor.blogspot.com/2019/01/cyanobacteria-superheroes-of-evolution_30.html" target="_blank"><i>Cyanobacteria</i></a></b>, which are still abundant today. Solid evidence of their existence goes back nearly 3 billion years, but they may have been present even earlier. (<a href="http://botanyprofessor.blogspot.com/2012/12/the-first-plants.html" target="_blank"><i>The first plants</i></a>) (<a href="https://botanyprofessor.blogspot.com/2019/01/cyanobacteria-superheroes-of-evolution_30.html" target="_blank"><i>Cyanobacteria - the super heroes of evolution</i></a>)<p></p><p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj99cfUhJEBrnvMIja5-yGDKoKhPoCWUVhb3RCB5z7MyItPF9FF5fqsc8_hp46pqojA41aPpg9kWrPrKEOjsjjwKQ5sRcKd9EVKJKv8NP2usB-ZFRA5vCpGYZ9vlovNVZsEUGiRtH9GwHOACorwU4sREmqB2lwmrLP-iaL89zSlhKAfVjLBhGRAiWR7sg/s500/Chlamydomonas_globosa_-_400x_(13263097835).jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="500" data-original-width="500" height="152" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj99cfUhJEBrnvMIja5-yGDKoKhPoCWUVhb3RCB5z7MyItPF9FF5fqsc8_hp46pqojA41aPpg9kWrPrKEOjsjjwKQ5sRcKd9EVKJKv8NP2usB-ZFRA5vCpGYZ9vlovNVZsEUGiRtH9GwHOACorwU4sREmqB2lwmrLP-iaL89zSlhKAfVjLBhGRAiWR7sg/w152-h152/Chlamydomonas_globosa_-_400x_(13263097835).jpg" width="152" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;"><i>Chlamydomonas</i>, a single-<br />celled alga CC by-SA 2.0</span></td></tr></tbody></table><br /><p></p><p></p>3. <b>Origin of eukaryotic algae</b> - Primitive animal-like cells, already equipped with mitochondria, captured cyanobacteria through <i style="font-weight: bold;">endosymbiosis, </i>which were "domesticated" to become <b>chloroplasts</b>. (<a href="http://botanyprofessor.blogspot.com/2011/10/plants-and-animals-and-kleptoplasts-oh.html" target="_blank"><i>Plants and animals and kleptoplasts - oh my!</i></a>) This occurred a number of times, resulting in multiple unrelated organisms called <b>algae, </b><i style="font-weight: bold;"> </i>which at first floated as part of the phytoplankton of the seas. Sexual reproduction via cells specialized as sperm and egg evolved in these early algae, along with mitosis and meiosis.<p></p><p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-MCPzYszbe7Q2REQB9TJZYEPmH_TXZw39oex3rAYzzMLU1MRyxNLK_lG0uLflaBwCH1nIzrU1k1MAMnyGtIzO1y2gZ_x7u2b9qMGDt5iA0maO9DvEB_5i9ujljV_cJd1ePQAMnmFy-SlgUlvr0QjCdnqahsFH-Azu2PyJ5Jgnj0bg2rgWMOhse36P7g/s1782/CharaFragilis.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1782" data-original-width="1220" height="214" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-MCPzYszbe7Q2REQB9TJZYEPmH_TXZw39oex3rAYzzMLU1MRyxNLK_lG0uLflaBwCH1nIzrU1k1MAMnyGtIzO1y2gZ_x7u2b9qMGDt5iA0maO9DvEB_5i9ujljV_cJd1ePQAMnmFy-SlgUlvr0QjCdnqahsFH-Azu2PyJ5Jgnj0bg2rgWMOhse36P7g/w146-h214/CharaFragilis.jpg" width="146" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Freshwater charophytes<br />are related to land plants</span></td></tr></tbody></table><br /><p></p><p></p><br /><p></p><p>4. <b>Origin of multicellular plants</b> - With cells remaining attached to one another, and usually also anchored to rocks and other substrates, multicellular algae were able to branch into extensive light-gathering antenna systems, resulting in the various kinds of seaweeds and freshwater plants like charophytes.<b></b></p><p><b><b><br /></b></b></p><p><b><b><br /></b></b></p><b><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYgiX6FhQaGs0GYBTP0J7-lvYFuEJyEZOmFCxM5Gf3nv9pz8tVwTwJuZf1zHKl5WBm06QytYWo1tKa86gvHkG0WKZhvVMQ9OsOr8Q5UTp9NjQKABOIkvgc41WgdZ4C4C-93hZh3mgaC8HUHN59tef4hh8cBZhd14Ck0XWrbSTknBPZc38RyDYOaPzjrA/s937/Sphagnum%20recurvum%20Eco%20Area.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="937" data-original-width="624" height="211" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYgiX6FhQaGs0GYBTP0J7-lvYFuEJyEZOmFCxM5Gf3nv9pz8tVwTwJuZf1zHKl5WBm06QytYWo1tKa86gvHkG0WKZhvVMQ9OsOr8Q5UTp9NjQKABOIkvgc41WgdZ4C4C-93hZh3mgaC8HUHN59tef4hh8cBZhd14Ck0XWrbSTknBPZc38RyDYOaPzjrA/w140-h211/Sphagnum%20recurvum%20Eco%20Area.jpg" width="140" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Mosses were among the <br />earliest land plants, and <br />continue to thrive in moist <br />habitats. Modern <i>Sphagnum</i> <br />mosses pictured here form <br />vast peat bogs, particularly <br />in boreal regions.<br /></span><br /></td></tr></tbody></table><br />5. Invasion of the land </b>- Green algae adapted already to freshwater habitats, colonized the land, becoming the ancestors of both <b>bryophytes</b> (mosses, liverworts, and hornworts) and <b>tracheophytes</b> <b> (</b><b>vascular plants </b>like ferns, gymnosperms, angiosperms<b>)</b>. Early land plants survived by developing water-retaining outer layers and internal systems for storing and transporting water. While such plants remained close to bodies of water at first, they created the vegetation that supported the first animal life to leave the water. The hydrostatic, or <b>turgor,</b> pressure within terrestrial plant cells maintains cell and tissue rigidity and drives cell expansion. It also drives the transport of food-laden fluid in the <b>phloem</b> tissue water and, in combination with evaporation and transpiration, helps drive the movement of water from the roots to the leafy plant tops, even in trees 100 meters tall. (<a href="http://botanyprofessor.blogspot.com/2011/11/how-does-water-get-to-top-of-redwood.html" target="_blank"><i>How does water get to the top of a redwood tree?</i></a>) Turgor pressure is also the basis of plant movements, such as the closing of of leaf traps in the Venus fly trap. (<a href="http://botanyprofessor.blogspot.com/2015/01/how-plants-do-everything-without-moving.html" target="_blank"><i>How plants do everything without moving a muscle</i></a>?)<p></p><p></p><br /><div><br /></div><div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4ZBlHFO6pcv1UAPIc2IU1jBmziViIGxGfk7o6jEi8kza8ioIurPaygiMkjXA2FTEhcfwireQFO_pHNMWyP-D8J4NxbN3iN7mEqNtWFodh4_7tuI6gdHwdcDqneXMp2GvEca5qriayF-3ygYG9vYW_Iu83_D1JCYcuVo9sNEvy7rz836duc_0zocywGg/s1440/1440px-Fern_spores_P1180804.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1080" data-original-width="1440" height="156" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4ZBlHFO6pcv1UAPIc2IU1jBmziViIGxGfk7o6jEi8kza8ioIurPaygiMkjXA2FTEhcfwireQFO_pHNMWyP-D8J4NxbN3iN7mEqNtWFodh4_7tuI6gdHwdcDqneXMp2GvEca5qriayF-3ygYG9vYW_Iu83_D1JCYcuVo9sNEvy7rz836duc_0zocywGg/w208-h156/1440px-Fern_spores_P1180804.jpg" width="208" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Ferns produce wind-dispersed spores <br />that sprout into gametophytes.</span></td></tr></tbody></table>6. <b>Invention of wind-dispersed spores.</b> In the earliest land plants, and still in modern bryophytes and seedless vascular plants like ferns, sexual reproduction was essentially unchanged from what it was in aquatic algae. Sperm cells had to swim to eggs through water-filled channels and films in the soil. Since the distance sperm cells could travel was very limited, early plants produced dormant, wind-dispersed spores through meiosis from diploid <b>sporophyte</b> plants that developed from fertilized eggs. Spores could carry genetic information between populations, thus promoting genetic diversity and greater adaptability. Spores germinated into haploid gametophyte plants that produced another round of sperm and egg.(<a href="http://botanyprofessor.blogspot.com/2011/11/truth-about-sex-in-plants.html" target="_blank">The truth about sex in plants</a>) </div><div><p></p><br /><b><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBjz0alXqDUtwhxKaj5Dddm_s7uI9oeglJQiZBwQQftrTz09ScOygf_36fdZoudaERT8HvJO3quym0F4MAClxHjQCHwsmrogt5Ueuory_MXr2gYrLJ_ms9sfin8dR-ywWEiUB8YFRkxaHSnH8xjYYWlWZINnb5RWmNUPHOtSzAYZ9q1oFvPwDxY6NgDQ/s1544/2005-03A_23A%20USFBG%20Cycas%20circinalis.JPG" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1544" data-original-width="1024" height="235" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBjz0alXqDUtwhxKaj5Dddm_s7uI9oeglJQiZBwQQftrTz09ScOygf_36fdZoudaERT8HvJO3quym0F4MAClxHjQCHwsmrogt5Ueuory_MXr2gYrLJ_ms9sfin8dR-ywWEiUB8YFRkxaHSnH8xjYYWlWZINnb5RWmNUPHOtSzAYZ9q1oFvPwDxY6NgDQ/w155-h235/2005-03A_23A%20USFBG%20Cycas%20circinalis.JPG" width="155" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">Ovules contain the stages of <br />reproduction, </span><span style="font-size: small;">from spore, <br />to gametophyte, to embryo</span><br style="font-size: small;" /><span style="font-size: small;">surrounded by food (seed). <br />In this cycad, ovules are <br />borne on modified leaf-like <br />structures.</span></td></tr></tbody></table><br /></b>6. <b>Evolution of the seed - </b>The seed, called in its early development an <b>ovule,</b> is both a chamber for internal sexual reproduction<b> </b>and a vehicle for the dispersal of the embryo once it matures. Eggs are produced by highly reduced gametophyte plants within the ovules, while sperm cells are produced by even smaller gametophyte plants within specialized spores called <b>pollen grains</b>, which are brought to the ovule by wind or insects. This liberates plants from the need for water-transmission of sperm to egg, enabling them to live and reproduce in drier habitats, the same way as internal fertilization and laying of desiccation-resistant eggs allowed reptiles to spread through dry terrestrial habitats. The earliest seed plants, took the form of <b>seed ferns</b>, in which pollen-producing sporangia (<b>pollen sacs</b>) and ovules were borne directly on large, fern-like leaves. In more advanced gymnosperms, pollen and ovule forming leaves became distinct from the vegetative leaves and took different forms, most often scale-like structures grouped into strobili (<b>cones </b>if rigid, <b>catkins</b> if soft and flexible). Among living gymnosperms, only some cycads have ovule-bearing structures that still resemble leaves. </div><div><p></p><p></p><br /></div><div><br /></div><div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUGCQ_KfG0BWCdnfT4yNjlil-mT6OFDI0r5HZFFo3m5iGUjDon8CE8GI-txFvl-0sFxfkLyPwWxYi_hlWxra-umuPAqHX96QcCFSFflu15mWfJLtFiW4BoMFKnZrHuyr5u_47aXNoKnKySc2WdRhVgWNtiQTvwtT2PVED711cc6X-05droKALrZlxEdA/s2953/03181%20Magnolia.JPG" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1988" data-original-width="2953" height="164" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUGCQ_KfG0BWCdnfT4yNjlil-mT6OFDI0r5HZFFo3m5iGUjDon8CE8GI-txFvl-0sFxfkLyPwWxYi_hlWxra-umuPAqHX96QcCFSFflu15mWfJLtFiW4BoMFKnZrHuyr5u_47aXNoKnKySc2WdRhVgWNtiQTvwtT2PVED711cc6X-05droKALrZlxEdA/w244-h164/03181%20Magnolia.JPG" width="244" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Magnolia flowers have numerous distinct <br />carpels (uppermost), numerous stamens, all<br />subtended by a number of tepals (petals/sepals)<br /><br /></span></td></tr></tbody></table>7. <b>Origin of the flower</b> - flowers evolved as a means of manipulating insects and other animals for transfer of pollen from one plant to another (<b>pollination)</b>. The seemingly endless diversity of flowers is reflected in an equal diversity of insects, birds, and other animals adapted to recognize and feed in flowers with specific combinations of shape, color, fragrance, and nectar production. Flowering plants, or <b>angiosperms</b>, evolved from ancient seed ferns in parallel with the various groups of modern gymnosperms. Their pollen-bearing structures (<b>stamens</b>) and ovule-bearing structures (<b>carpels</b>), are surrounded by leaf-like <b>petals</b> and <b>sepals</b>, and arranged in a distinctive order in each <b>flower</b>. Carpels mature as <b>fruits</b> that aid in the dispersal of seeds. (<a href="http://botanyprofessor.blogspot.com/2014/07/whats-so-primitive-about-amborella.html" target="_blank">What's so primitive about <i>Amborella</i>?</a>)<p></p><p></p><p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8cjzvpT51Y9QxM8DiFVjwAsdmwmHGpWis4UieZbAXHd0Bljefkwjm0WcwdfU_zpe69k6zj2jrpsILXyP4haRIb8BEUTfas_jwKQB6XjtzHv9jZepvHAa7Q3QDZV4DKszWnzKZ_hImQv-8h0E9kRSAA1Ynzad0Skp2N003fSZzcfp6AEKDS2kULrfI7Q/s1440/1440px-Grasses_in_the_Valles_Caldera_2014-06-26.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1080" data-original-width="1440" height="179" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8cjzvpT51Y9QxM8DiFVjwAsdmwmHGpWis4UieZbAXHd0Bljefkwjm0WcwdfU_zpe69k6zj2jrpsILXyP4haRIb8BEUTfas_jwKQB6XjtzHv9jZepvHAa7Q3QDZV4DKszWnzKZ_hImQv-8h0E9kRSAA1Ynzad0Skp2N003fSZzcfp6AEKDS2kULrfI7Q/w239-h179/1440px-Grasses_in_the_Valles_Caldera_2014-06-26.jpg" width="239" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Grasses dominate extensive areas with<br />alternating wet and dry seasons. Photo by V. S.<br />Dustin CC BY SA-3.0</span></td></tr></tbody></table><br />8.<b> Re-evolution of the herbaceous habit - </b>While ferns and other non-seed-bearing plants were herbaceous, early seed plants and all gymnosperms are woody, as required for the slow development and maturation of their seeds. Angiosperms further shortened the reproductive cycle, so as to make quick-growing, winter-dormant herbs possible again. The most significant group of angiosperm herbs are the monocots, with grasses being the most widespread and ecologically significant herbs on the planet. (<a href="http://botanyprofessor.blogspot.com/2012/01/how-grass-leaf-got-its-stripes.html">How the grass leaf got its stripes</a>) (<a href="http://botanyprofessor.blogspot.com/2012/03/grasses-that-would-be-trees.html">The grasses that would be trees</a>) Grasses support vast food webs on seasonally dry savannas, and their seeds provide the major source of sustenance for humans around the globe. <p></p><p>9. <b>Evolution of varied secondary plant compounds</b> - All through the evolution of plants, which are both nutritious and immobile, animals evolved to feed upon them. While some plants, like many algae and grasses, could multiply fast enough to overcome such predation, many other plants have evolved deterrents, including hard fibers and various forms of spines, thorns, etc., but most importantly toxic or repellant chemicals. Plant chemicals that deter animal herbivores have become numerous and diverse as different species of animals developed immunity to some but not all. By nature, secondary plant compounds are physiologically active and while poisonous in some circumstances, often have valuable medicinal effects. As such, they have been vital to the survival of the human species. (<a href="http://botanyprofessor.blogspot.com/2014/05/medicinal-plants-in-our-own-backyard.html" target="_blank">Medicinal plants in our own backyard</a>)</p><p><br /></p></div>Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-18236757470142506542020-12-09T06:47:00.000-08:002020-12-09T06:47:32.038-08:00A perfect storm of weeds<p></p><br /><br /> A weed is sometimes defined as a plant out of place - or more often an overwhelming mass of plants popping up where we don't want them. It's a definition based on our futile attempts to to remake a landscape into something a human vision of tidiness. To be fair weeds are often exotic plants - invasive species from another continent freed from their usual constraints of competitors and predators. And so, weeds are also bad for our natural ecosystems, not just to our landscaping vanity.<p></p><p>Weeds are mostly plants that are really good at spreading into disturbed habitats. They multiply rapidly, often asexually, and fill vacant ground or the exposed sides of forests. They are a vital part of succession, preserving soil, nutrients and moisture. And so such plants are good for their native ecosystems. Our native grape vines and blackberries, however, can also become a nuisance at the edge of woods, sometimes creeping into yards, and so give the landscaper an ethical dilemma.</p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-YbwHhXJ9OsY/X8_0WKkbrXI/AAAAAAAAEZA/53MKUOW-WXQ0HNHpzkjDoJnAjVuRTv3EACLcBGAsYHQ/s2048/10817%2BIpomoea%2Breclaiming%2Broad.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1336" data-original-width="2048" height="418" src="https://1.bp.blogspot.com/-YbwHhXJ9OsY/X8_0WKkbrXI/AAAAAAAAEZA/53MKUOW-WXQ0HNHpzkjDoJnAjVuRTv3EACLcBGAsYHQ/w640-h418/10817%2BIpomoea%2Breclaiming%2Broad.jpg" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">A native species of morning glory begins to reclaim an abandoned logging road in Papua New Guinea</span>.<br /></td></tr></tbody></table><p></p><p><br /></p><p><br /></p><p><br /></p><p>Up north, fastidious weed-haters spend hours in the </p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-T1xJ_W7zbqQ/X81LmQUWtjI/AAAAAAAAEX8/WZBDtepbvA0J48EMVmCxrz9Mbt3fYiNDQCLcBGAsYHQ/s1975/20201202_112537.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1975" data-original-width="1601" height="320" src="https://1.bp.blogspot.com/-T1xJ_W7zbqQ/X81LmQUWtjI/AAAAAAAAEX8/WZBDtepbvA0J48EMVmCxrz9Mbt3fYiNDQCLcBGAsYHQ/w259-h320/20201202_112537.jpg" width="259" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;"><i>Syngonium (Nepthytis) podophyllum </i>is valued as<br />a house plant, but it can escape into native woods.<br />Here it clambers into a conservation area near a<br />housing development in Florida.</span></td></tr></tbody></table><p>spring and summer pulling up dandelions one-by-one from their lawns, only to have them repopulate the next season from the one that got away, its seeded parachutes having been blown across the yard by a visiting grandchild.</p><p></p><p>While you in the north can relax during the winter, we in Florida, continue to battle with the "Vines from Hell" that never take a rest. Our nastiest weeds are climbers and creepers that can smother a bush within months, or just as easily march through beds and across lawns. They are vines that not only grow upward, but also on the ground, sprouting roots as they go, and this is where they are most troublesome. A simple vine can be severed at the base and pulled from the trees, but removing the rooted bits of one of these creepers from the soil is a nightmare. We chop them up, pull them up, dig them up, but if we leave one tiny fragment, it will come to life again like the splinters of the broomsticks in the Sorcerer's Apprentice. All it takes is a single node, with a single tiny bud.</p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-TaSX2dMbK0g/X8bNat2NTLI/AAAAAAAAEXY/-6EFt3US_RoNPLCrIY5-Y7a7-nS6UXKYQCPcBGAYYCw/s2048/20201002_181344.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2048" data-original-width="1536" height="400" src="https://1.bp.blogspot.com/-TaSX2dMbK0g/X8bNat2NTLI/AAAAAAAAEXY/-6EFt3US_RoNPLCrIY5-Y7a7-nS6UXKYQCPcBGAYYCw/w300-h400/20201002_181344.jpg" width="300" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Missed bits of <i>Syngonium </i>resprout in an area that<br />was recently cleared of it.</span></td></tr></tbody></table><p></p><p>So in our Florida yards some of our worst weed nightmares are Nepthytis (<i>Syngonium podophyllum</i>), flame vine <i>Pyrostegia venusta</i>), air potato vine (<i>Dioscorea bulbifera</i>), and skunkvine (or stinkvine), (<i>Pedaria foetida</i>). Skunkvine comes from tropical Asia and air potato from tropical Asia and Africa. Flame vine and Nepthytis come from tropical America. </p><p>The air potato is a member of the true Yam Family (Dioscoreaceae), while sweet potatoes, which are sometimes called yams, are in the Morning Glory Family (Convulvulaceae). Real potatoes are in the Tomato Family (Solanaceae). Air potatoes can evidently now be controlled by a beetle from Nepal, and so is not seen in Florida quite as much.</p><p>There are a couple more that don't climb trees, but are even more adept at creeping horizontally through beds and lawns. The Boston fern (<i>Nephrolepis exaltata</i>), a popular house plant, will escape into moist woods and form dense colonies in Florida. It is a native of tropical regions around the world, and will actually freeze to death if it attempts to escape anywhere near Boston! Marsh pennywort (<i>Hydrocotyle vulgaris</i>), native to Europe and North Africa, can choke out lawn grass, particularly in moist areas near ponds.</p><p></p><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-idQ0IFds_n0/X8bOe6oxZ7I/AAAAAAAAEXs/XAlI5feaaU0MDEhhFEctQ02_8Gl_txOpQCPcBGAYYCw/s2048/20200801_094813.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1536" data-original-width="2048" height="480" src="https://1.bp.blogspot.com/-idQ0IFds_n0/X8bOe6oxZ7I/AAAAAAAAEXs/XAlI5feaaU0MDEhhFEctQ02_8Gl_txOpQCPcBGAYYCw/w640-h480/20200801_094813.jpg" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">One of the most rampant vining weeds in central Florida is Skunkvine, here twining its way through a <i>Ligustrum</i> hedge.</span></td></tr></tbody></table><br /><br /><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-QJyB_XoQajo/X81ST2SSA5I/AAAAAAAAEYU/YHHND48rucMtt8KcWzddINkZkqiyQ0NoACLcBGAsYHQ/s2048/9958%2BPyrostegia.JPG" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2048" data-original-width="1362" height="400" src="https://1.bp.blogspot.com/-QJyB_XoQajo/X81ST2SSA5I/AAAAAAAAEYU/YHHND48rucMtt8KcWzddINkZkqiyQ0NoACLcBGAsYHQ/w266-h400/9958%2BPyrostegia.JPG" width="266" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Flame vine is an attractive ornamental vine, <br />but it can smother trees and also spread across<br />the ground, rooting as it goes.</span></td></tr></tbody></table><br /> <div><br /></div><div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1_iQ3quFg5W65aAU6BT7pjtLi0cU0QQRYNSZt_vrJP0dPKHQCugjqvMdbENqD4TaGIZj1nrs8xhdKJY8oJ_1-2UOp034ximvW4pFUZ1kVTlv7HIwNUi-EIY3z8xgXn-ZsGH3BPBs5fyOI/s2048/20201128_112408.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2048" data-original-width="1536" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg1_iQ3quFg5W65aAU6BT7pjtLi0cU0QQRYNSZt_vrJP0dPKHQCugjqvMdbENqD4TaGIZj1nrs8xhdKJY8oJ_1-2UOp034ximvW4pFUZ1kVTlv7HIwNUi-EIY3z8xgXn-ZsGH3BPBs5fyOI/w300-h400/20201128_112408.jpg" width="300" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Boston fern seems to be an innocuous house or bedding <br />plant, but can form thickets in moist woodlands when it <br />escapes. It extends horizontally through the soil by<br />slender runners that sprout new plants every few feet.</span></td></tr></tbody></table></div><div><br /></div><div>T<br /><br /><br /><p></p></div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-aLJ1Hz0oJ6Q/X81Yk6bNyEI/AAAAAAAAEYg/InrJbb-Y4iYcCrdSUpq3BHGqZRqG4UWjgCLcBGAsYHQ/s1536/2004-05-21%2BHydrocotyl%2Bflowers.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1037" data-original-width="1536" height="270" src="https://1.bp.blogspot.com/-aLJ1Hz0oJ6Q/X81Yk6bNyEI/AAAAAAAAEYg/InrJbb-Y4iYcCrdSUpq3BHGqZRqG4UWjgCLcBGAsYHQ/w400-h270/2004-05-21%2BHydrocotyl%2Bflowers.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">The flowers of pennywort are in umbels, demonstrating its <br />relationship to members of the Carrot Family (Apiaceae or <br />Araliaceae). Seed production is not important for local<br />spreading, but is likely responsible for long-distance dispersal.</span></td></tr></tbody></table><div class="separator" style="clear: both; text-align: center;"><br /></div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-aWltPKBt8lE/X81Y25r5zMI/AAAAAAAAEYs/o4ZxOoGUibY0C97E2HA1MmfIUWGSK-p1QCLcBGAsYHQ/s2048/2003-10-02%2BDioscorea%2Bleaves.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2048" data-original-width="1382" height="400" src="https://1.bp.blogspot.com/-aWltPKBt8lE/X81Y25r5zMI/AAAAAAAAEYs/o4ZxOoGUibY0C97E2HA1MmfIUWGSK-p1QCLcBGAsYHQ/w270-h400/2003-10-02%2BDioscorea%2Bleaves.jpg" width="270" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Air potato vine is a member of the true Yam<br />Family (Dioscoreaceae). It clambers into <br />trees</span>.</td></tr></tbody></table><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><br /><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-ajYtxtZYSo0/X81Yv20heiI/AAAAAAAAEYk/dhbA8UOrw50izbJAVsc-wl8oYW056fLqQCLcBGAsYHQ/s315/air-potato-5344014.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="230" data-original-width="315" src="https://1.bp.blogspot.com/-ajYtxtZYSo0/X81Yv20heiI/AAAAAAAAEYk/dhbA8UOrw50izbJAVsc-wl8oYW056fLqQCLcBGAsYHQ/s0/air-potato-5344014.jpg" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">Air potato vines produce small tubers on their<br />stems, which fall to the ground and start new vines.<br />Caution - they are not edible. Photo by Karen Brown; <br />University of Florida; posted on USDA National<br />Invasive Species Information Center. </span></td></tr></tbody></table><br />Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-91114226209500124302020-08-04T14:25:00.002-07:002020-08-04T14:38:55.668-07:00Grasping at Straws<div class="separator" style="clear: both; text-align: left;"><span>Vining plants have an amazing ability to grab onto a trellis, fence, or a twig on another plant by curling around it. It's an adaptation that allows the vine to grow rapidly upward using other objects for support. This gives them a distinct advantage over tree or shrub saplings that need to build their own woody support as they grow upwards. But how does it work? </span></div><div class="separator" style="clear: both; text-align: left;"><span><br /></span></div><div class="separator" style="clear: both; text-align: left;"><div class="separator" style="clear: both;">The process is called <b>thigmotropism</b>, or touch-induced growth response. Specialized organs called <b>tendrils</b>, or sometimes the stem of a young plant itself, can sense contact with a nearby object and alter their growth pattern so as to bend toward it. If the object is rigid enough and not too thick, the tendril or stem will continue to bend and coil around it. </div><div class="separator" style="clear: both;"><br /></div></div><div class="separator" style="clear: both; text-align: left;"><br /></div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-uTKXJw_YaVc/XySFX_8JwbI/AAAAAAAAEUc/iafIpNWTFKMvFqRHs-twh7g2LQW2p1JjgCLcBGAsYHQ/s2048/20200727_093219.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1263" data-original-width="2048" height="253" src="https://1.bp.blogspot.com/-uTKXJw_YaVc/XySFX_8JwbI/AAAAAAAAEUc/iafIpNWTFKMvFqRHs-twh7g2LQW2p1JjgCLcBGAsYHQ/w410-h253/20200727_093219.jpg" width="410" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-family: arial; font-size: small; text-align: left;">The tendrils of a bitter melon vine stretch out ahead of the shoot apex.</span></td></tr></tbody></table><blockquote style="border: none; margin: 0px 0px 0px 40px; padding: 0px;"><div class="separator" style="clear: both;"><br /></div></blockquote><div class="separator" style="clear: both; text-align: left;"><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilvM5D6B-BcJLKSGZIS8vH9Tm6pgsQy6erNRETEMAiQCpwyz9cBj_cFmaqKbBC1zGak7NQqzJmH6HVYHWsDLf7lMhLvfEleDM0yNWxIYCvYE4sDU9GJv5PC5aALiaoSU3KUQD8bxZ7g-_S/s2048/20200727_092929flip.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1753" data-original-width="2048" height="350" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEilvM5D6B-BcJLKSGZIS8vH9Tm6pgsQy6erNRETEMAiQCpwyz9cBj_cFmaqKbBC1zGak7NQqzJmH6HVYHWsDLf7lMhLvfEleDM0yNWxIYCvYE4sDU9GJv5PC5aALiaoSU3KUQD8bxZ7g-_S/w410-h350/20200727_092929flip.jpg" width="410" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">When a tendril encounters an object, such as this actual straw <br />recruited for the demonstration, it will grasp it by wrapping<br />around it.</td></tr></tbody></table></div><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><img height="384" src="https://1.bp.blogspot.com/-GqaeAoiSFwY/XySI2xVoEcI/AAAAAAAAEU8/XSgDRH-kVgcKSDFplOIv2nth8CSGB3g9wCLcBGAsYHQ/w512-h384/20200727_094516.jpg" style="margin-left: auto; margin-right: auto;" width="512" /></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-family: arial; font-size: small; text-align: left;">The tendril of a passion fruit vine seems to have tied itself into some kind of nautical knot </span><br style="font-family: arial; font-size: small; text-align: left;" /><span style="font-family: arial; font-size: small; text-align: left;">to secure its support on a fence.<br /><br /></span></td></tr></tbody></table><div> Thigmotropism is similar to phototropism and gravitropism, which are the bending responses to light and gravity respectively. </div><div><br /></div><div>In the light response, light-sensitive pigments create an inhibition of the growth hormone, auxin, on the lit side and then the opposite side grows faster, bending the stem toward the light. </div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div><br /></div><div>Gravitropism comes into play underground, causing roots to grow downward and buried shoots to grow upward. For example, if a root emerges from a sprouting seed sideways, tiny crystals in the cells of the root tip, called statoliths, settle downward to the lower surface of the root, causing the upper side of the root to grow faster and bending the tip downward.</div><div><br /></div><div class="separator" style="clear: both;">The mechanism in thigmotropism is not as clear and not always the same. Since thigmotropism occurs in different kinds of organs in different plants, it has certainly evolved independently many times. For example, just within the Legume Family, peas have evolved to climb by tendrils, while beans climb by twining their stems around a support.</div><div class="separator" style="clear: both;"><br /></div><div class="separator" style="clear: both;"> In general though, the touch of an object deforms the surface of the epidermal cells, and growth closest to the object is suppressed. Continued growth on the opposite side causes the stem or tendril to coil around the support. </div><div class="separator" style="clear: both;"><br /></div><div class="separator" style="clear: both;"><br /></div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-6YwtkNEjPZM/XyXGx5VJlRI/AAAAAAAAEVU/fXd-yF0afTgW9QczoEL62HMI3JBsPXL2gCLcBGAsYHQ/s2048/20200801_094646.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2048" data-original-width="1536" height="640" src="https://1.bp.blogspot.com/-6YwtkNEjPZM/XyXGx5VJlRI/AAAAAAAAEVU/fXd-yF0afTgW9QczoEL62HMI3JBsPXL2gCLcBGAsYHQ/s640/20200801_094646.jpg" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">In the noxious weed, skunk vine, the stems themselves wrap around<br />the support. Bean plants twine in the same way.</td></tr></tbody></table><div class="separator" style="clear: both; text-align: center;"><br /></div><blockquote style="border: none; margin: 0px 0px 0px 40px; padding: 0px;"><div class="separator" style="clear: both;"><blockquote style="border: none; margin: 0px 0px 0px 40px; padding: 0px;"><div class="separator" style="clear: both;"><br /></div></blockquote></div></blockquote><div class="separator" style="clear: both; text-align: center;"><br /></div><div class="separator" style="clear: both; text-align: left;"><br /></div><div class="separator" style="clear: both; text-align: left;"><div class="separator" style="clear: both;"><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-ThThDotiOnU/XyXJviZokDI/AAAAAAAAEVg/ho6mPayliP0-bcFlnLBJlTC9UeAUGXPawCLcBGAsYHQ/s275/images.jpeg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="275" data-original-width="183" height="673" src="https://1.bp.blogspot.com/-ThThDotiOnU/XyXJviZokDI/AAAAAAAAEVg/ho6mPayliP0-bcFlnLBJlTC9UeAUGXPawCLcBGAsYHQ/w448-h673/images.jpeg" width="448" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Tendrils may be separate organs, or in the case of this climbing lily, <br /><i>Gloriosa</i>, just the tip of the leaf. Photo by SAPlants, posted on Wikipedia, <br />CC-BY-SA-4.0.</td></tr></tbody></table><div class="separator" style="clear: both;"><br /></div><br /></div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-srKZS1dsJIE/XymBaFdvcyI/AAAAAAAAEWA/AshkEFvphrIkj4zvR7TwNvim7ElaGgitACLcBGAsYHQ/s766/08759%2BClematis%2Btendrils.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="766" data-original-width="715" height="512" src="https://1.bp.blogspot.com/-srKZS1dsJIE/XymBaFdvcyI/AAAAAAAAEWA/AshkEFvphrIkj4zvR7TwNvim7ElaGgitACLcBGAsYHQ/w478-h512/08759%2BClematis%2Btendrils.jpg" width="478" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">The genus <i>Clematis</i> is unique in the Buttercup Family, Ranunculaceae, <br />in its vining habit. Its young compound leaves are thigmotropic and can <br />wrap around slender objects.</td></tr></tbody></table><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-oyuZ4uQ0mZY/XyXXqR-dpzI/AAAAAAAAEV0/fpTJ__DsJyo7gCpvSr0SmEg8GBSTjsgiwCLcBGAsYHQ/s1820/14341%2BDrosera%2Bmacrantha%2Bclimbing%2Bwhite.jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1820" data-original-width="1196" height="640" src="https://1.bp.blogspot.com/-oyuZ4uQ0mZY/XyXXqR-dpzI/AAAAAAAAEV0/fpTJ__DsJyo7gCpvSr0SmEg8GBSTjsgiwCLcBGAsYHQ/s640/14341%2BDrosera%2Bmacrantha%2Bclimbing%2Bwhite.jpg" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Some climbing plants use a completely different means of <br />attaching to a support. The most unusual I've ever seen is this<br />climbing Sundew from southwestern Australia, which re-purposes<br />some of its sticky insect-catching leaves for attachment.</td></tr></tbody></table></div>Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-26280531265352571592020-07-05T03:56:00.000-07:002020-07-05T03:56:09.670-07:00The folded leaves of Iris<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXsa3oXKKFqoJoAbcaNEmnyp4u9jOoR9D2eJ5snXCxz5dcxmaBP2irrrwM3IP2o-TQPcexwOOxEbkJrVR7o35yMx1GcFfcVdCtUQdnqhjdgl5wyWUGyB-e1vmeIcvZ-Qp_P8D3fuzrX_hU/s1600/20200704_084540.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1200" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXsa3oXKKFqoJoAbcaNEmnyp4u9jOoR9D2eJ5snXCxz5dcxmaBP2irrrwM3IP2o-TQPcexwOOxEbkJrVR7o35yMx1GcFfcVdCtUQdnqhjdgl5wyWUGyB-e1vmeIcvZ-Qp_P8D3fuzrX_hU/s400/20200704_084540.jpg" width="300" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><div style="font-size: 12.8px;">
In this Bearded Iris the leaves are folded and flattened,</div>
<div style="font-size: 12.8px;">
<span style="font-size: 12.8px;">forming a fan perpendicular to the tip of the rhizome.</span></div>
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<div style="text-align: left;">
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Many members of the Iris Family exhibit a peculiar, fan-shaped arrangement of their leaves. Leaves that are lined up on two sides of the stem in a single plane are called <b>2-ranked</b>, or <b>equitant. S</b>uch an arrangement of leaves is not uncommon, occurring in the Traveler's Palm, <i>Ravenala madagascariensis</i>, for example.<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-L6HvY1vaJU8/T_w17xaIdxI/AAAAAAAAAoA/zWqz0kJ-O-Y6fftoAcsczO9kAekv75GQACPcBGAYYCw/s1600/Ravenala.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="596" data-original-width="382" height="400" src="https://1.bp.blogspot.com/-L6HvY1vaJU8/T_w17xaIdxI/AAAAAAAAAoA/zWqz0kJ-O-Y6fftoAcsczO9kAekv75GQACPcBGAYYCw/s400/Ravenala.jpg" width="255" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">In the Traveler's Palm, leaves are equitant, but have<br />
conventional, spreading blades, <span style="font-size: 12.8px;">with exposed upper and </span><br />
<span style="font-size: 12.8px;">lower </span>surfaces.</td></tr>
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-7daT4rvK5Ww/XwCE7ELZhLI/AAAAAAAAETQ/pHgDAxQ1YEEzqjPJs9P8FCUMeYBNY21ywCPcBGAYYCw/s1600/20200704_084530.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1200" height="400" src="https://1.bp.blogspot.com/-7daT4rvK5Ww/XwCE7ELZhLI/AAAAAAAAETQ/pHgDAxQ1YEEzqjPJs9P8FCUMeYBNY21ywCPcBGAYYCw/s400/20200704_084530.jpg" width="300" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The leaves of the Iris connect to the rhizome in a circle, as<br />
in most monocots, but above that,the the two<br />
sides fold together tightly forming a narrow channel<br />
through which newer leaves emerge. Still higher, the two<br />
sides of the leaf become completely joined together, forming<br />
what appears to be a simple, sword-shaped leaf blade.<br />
<br /></td></tr>
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-hzhavoNH2SI/XwCFIzhZnwI/AAAAAAAAETQ/9wajgQq5yqgmuEfBS50BLVBy0LjLT1v3ACPcBGAYYCw/s1600/20200617_174317%2B1.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1200" height="400" src="https://1.bp.blogspot.com/-hzhavoNH2SI/XwCFIzhZnwI/AAAAAAAAETQ/9wajgQq5yqgmuEfBS50BLVBy0LjLT1v3ACPcBGAYYCw/s400/20200617_174317%2B1.jpg" width="300" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The bud of a new inflorescence pushes up through the<br />
center of the fan.</td></tr>
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But what's most interesting in the Iris is that the leaves are folded, with the two sides fused together into a seemingly simple structure. <b> </b>It's as if someone has taken a hot iron and pressed the whole clump of leaves into a flat sheet in preparation for mounting in a herbarium. You can see such leaves in many members of <i>Iris, </i><i>Gladiolus</i>, and related genera. It has evolved independently in unrelated monocots such as <i>Acorus </i>(Acoraceae) and<i> Lachnanthes </i>(Haemodoraceae)<i>.</i><br />
<br />
Such folded leaves are called <b>unifacial</b> (one-faced), because both sides are actually the same side - technically the <b>abaxial</b> side. The upper, or <b>adaxial</b> side of the leaf is totally internalized.<br />
<br />
You can see the folding most obviously at the bases of the leaves where the two sides remain separate to form a leaf sheath. New leaves emerge from the center of the fan through the folded bases.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-YRQ_ssvPsNc/XwDU_cuCWoI/AAAAAAAAETc/-fX4GqYOElUVpPxdFUEDVx1kVuS5CZjYwCLcBGAsYHQ/s1600/20200620_103747.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1200" height="400" src="https://1.bp.blogspot.com/-YRQ_ssvPsNc/XwDU_cuCWoI/AAAAAAAAETc/-fX4GqYOElUVpPxdFUEDVx1kVuS5CZjYwCLcBGAsYHQ/s400/20200620_103747.jpg" width="300" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The inflorescence results from the elongation<br />
of the rhizome tip, with long internodes<br />
between leaves that are reduced in size. Each<br />
leaf is open at the base, but fused into a<br />
solid upper portion.</td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-HhZTrgb0siY/XwDVQnOTH_I/AAAAAAAAETk/fJ8zfUbPu8gus_k9mO8S6uQcaL08MWyYACLcBGAsYHQ/s1600/20200620_103714.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1200" height="400" src="https://1.bp.blogspot.com/-HhZTrgb0siY/XwDVQnOTH_I/AAAAAAAAETk/fJ8zfUbPu8gus_k9mO8S6uQcaL08MWyYACLcBGAsYHQ/s400/20200620_103714.jpg" width="300" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Like the leaves in the main fan, those on the inflorescence <br />
stalk are open at the base, but fused together in the upper part.</td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgP9ppbIMYkC4cz4vWPOq5wAy647WbhHUIfNvj-dkJy2jcaa4FV4Ebi3GRGRjIHc8G3OJSN05fXAP5p2O7tfZjKq6ajyCUc1BysM5qz39jIq-V3ydnpF9D9bIqmRwusjlow4XpKKbCv0PJg/s1600/20200626_094022.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1200" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgP9ppbIMYkC4cz4vWPOq5wAy647WbhHUIfNvj-dkJy2jcaa4FV4Ebi3GRGRjIHc8G3OJSN05fXAP5p2O7tfZjKq6ajyCUc1BysM5qz39jIq-V3ydnpF9D9bIqmRwusjlow4XpKKbCv0PJg/s640/20200626_094022.jpg" width="480" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Ultimately, the spectacular flowers of the Bearded Iris open, beginning at the top. Other flowers<br />
will emerge from the bracts lower down. Incidentally, this is a rare sight in central Florida, where these pictures were taken. Only recently have "reblooming" varieties of the Bearded Iris been grown successfully here.</td></tr>
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Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-23377904511884219592020-05-03T13:54:00.001-07:002020-05-03T13:54:35.300-07:00The Leafy Origins of Sepals<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-4Aq21hlIV5U/Xq8VXVSvFKI/AAAAAAAAEOc/TTgagnKmD9wm2D5TtOktnNgl-GUHz6lxQCLcBGAsYHQ/s1600/20200318_164232.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1445" data-original-width="1600" height="361" src="https://1.bp.blogspot.com/-4Aq21hlIV5U/Xq8VXVSvFKI/AAAAAAAAEOc/TTgagnKmD9wm2D5TtOktnNgl-GUHz6lxQCLcBGAsYHQ/s400/20200318_164232.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The sepals of a rose bud are green and photosynthetic<br />
like fully developed leaves, and like the one on the left, <br />
sometimes even appear to partially subdivided like full<br />
leaves.</td></tr>
</tbody></table>
From an evolutionary point-of-view, it is generally accepted that the parts of the flower originated as modified leaves. Though there is controversy about the nature of the earliest carpels and stamens, the leaf-like nature of petals and sepals is abundantly evident. Sepals are generally the most leaf-like, no doubt because they are the most recently evolved of the flower parts, and may have originated separately in different lines of early angiosperms. <br />
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In some archaic flowering plants, such as <i>Magnolia</i>s, petals and sepals intergrade, with no clear distinction between the two, and they are called tepals.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgr9r-ZsH4r1soAEAnnrygFsK4JWk7Ht4n1pxARAIXDk2K1aYsbQeA9K4gy1f1wkfjn4_5avCnY2oi9uDFM5HfjwVdUWn2KkaeJfp_JK7DQw9cCnnD4fEi9vApPJGOfCS53W2IJLz4GAbYB/s1600/640px-Magnolia-x-alba-bud-comparison.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="480" data-original-width="640" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgr9r-ZsH4r1soAEAnnrygFsK4JWk7Ht4n1pxARAIXDk2K1aYsbQeA9K4gy1f1wkfjn4_5avCnY2oi9uDFM5HfjwVdUWn2KkaeJfp_JK7DQw9cCnnD4fEi9vApPJGOfCS53W2IJLz4GAbYB/s400/640px-Magnolia-x-alba-bud-comparison.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">In Magnolia, there is a series of similar outer, leaf-like<br />
structures that are colored like petals, though the outer ones<br />
serve to protect the bud during development, as specialized<br />
sepals do. Photo from Wikiwand, License: Creative <br />
Commons Attribution-Share Alike 3.0</td></tr>
</tbody></table>
Upon looking at a rosebud, the leaf-like nature of the sepal is evident. The occasional sepal that takes on even more of the subdivided shape of the full leaf, emphasizes the point. Leaves, bracts, sepals, and other flower parts develop from outgrowths of the apical meristem, and so in their earliest stages look the same. As each develops for its specific function, specialized genes kick in to determine the final shape, color, and other physical features of the organ. The fact that some rose sepals look a little more like normal leaves than others shows that the genes for full leaf development that are normally suppressed, can sometimes be partially expressed.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-n2aSACnTOw4/Xq8nQXmQW4I/AAAAAAAAEO0/flyo6RcbelAu5N7L849a47b98JnJYa9dQCLcBGAsYHQ/s1600/3201%2BClusia%2Bmod.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1065" height="640" src="https://1.bp.blogspot.com/-n2aSACnTOw4/Xq8nQXmQW4I/AAAAAAAAEO0/flyo6RcbelAu5N7L849a47b98JnJYa9dQCLcBGAsYHQ/s640/3201%2BClusia%2Bmod.jpg" width="424" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">In <i>Clusia</i>, the leaves are opposite with each pair at right angles to the<br />
preceding pair. A series of small bracts and two pairs of colored sepals<br />
continue the pattern. it's truly hard to see where bracts end and<br />
sepals begin.</td></tr>
</tbody></table>
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The development of similar, but modified, organs, from outgrowths of the apical meristem, is called <b>serial homology</b>. Homology in general refers to different body organs that were the same in ancestral species, but have become specialized for different functions in more specialized species. The classic examples in animals are front legs that have become specialized as wings in both birds and bats, and arms with grasping hands in primates. Serial homology can be seen in animals with segmented bodies. Insects and crustaceans, for example, descended from many-legged, centipede-like ancestors, but now have specialized walking legs, reproductive organs, claws, mouth parts, and other specialized organs, all representing modified legs.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjO-83bSERqB30cqWzLoUVU7cV78NvkR1-RyywF1TQF8PY8nCwcA-EeS93sSQmb8QiD2N8zUa0f1Yk3orXkaR7QTLwSTjurk1yGbYFuv3kzYQZVnlccJDsshTxEOtTZUbPiYkGFuy6AYE-9/s1600/3264+Lilium+mod.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1065" data-original-width="1600" height="265" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjO-83bSERqB30cqWzLoUVU7cV78NvkR1-RyywF1TQF8PY8nCwcA-EeS93sSQmb8QiD2N8zUa0f1Yk3orXkaR7QTLwSTjurk1yGbYFuv3kzYQZVnlccJDsshTxEOtTZUbPiYkGFuy6AYE-9/s400/3264+Lilium+mod.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Lilies, like many monocots, have what appear to be six petals,<br />but three of them are actually petal-like sepals</td></tr>
</tbody></table>
Serial homology of leaf-like organs in plants suggests that at one time there were only leaves, as in early seed ferns, that did everything: photosynthesis as well as bearing pollen sacs and ovules, and all had the same shape. As plants progressed, a division of labor came into being, with some leaves continuing the primary photosynthetic function, while others became specialized as bracts or floral organs. In previous posts I have described even more bizarre leaf modifications, such as insect-catching traps.<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-MHOt5kSFD7Y/Xq8qQmp4PoI/AAAAAAAAEPM/hNLJ0X9C5qIt40OSvfkeGc8vK2HX_EIBgCLcBGAsYHQ/s1600/01778%2BTrillium.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1076" data-original-width="1600" height="268" src="https://1.bp.blogspot.com/-MHOt5kSFD7Y/Xq8qQmp4PoI/AAAAAAAAEPM/hNLJ0X9C5qIt40OSvfkeGc8vK2HX_EIBgCLcBGAsYHQ/s400/01778%2BTrillium.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i>Trilliums</i> are monocots only distantly related to the true lilies,<br />and display three leaf-like sepals, most likely as did the <br />ancestral monocots.</td></tr>
</tbody></table>
The ancestral set of genes that orchestrated the <br />
development of leaves was supplemented with new sets of genes that served to modify the embryonic leaves for specialized functions. The new sets of genes both suppressed the full development of the original leaf size and shape and directed the development of specialized features. Serial homology along a single shoot, from leaves to bracts to flower parts, shows that these different sets of genes are turned on and off in an orderly way.Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-35502875624242383662020-03-22T08:47:00.002-07:002020-03-22T08:59:48.629-07:00Why are Anthuriums red?<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-3ZRTWBZ9DnI/XnZ7AcloToI/AAAAAAAAENk/9vqAUHXOuTwMggaotFn_ymMAwgOKALCOACEwYBhgL/s1600/20200317_115051.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1200" height="400" src="https://1.bp.blogspot.com/-3ZRTWBZ9DnI/XnZ7AcloToI/AAAAAAAAENk/9vqAUHXOuTwMggaotFn_ymMAwgOKALCOACEwYBhgL/s400/20200317_115051.jpg" width="300" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">One of my favorite plants is this cultivar of<br />
<i>Anthurium andreanum</i>, with spathes of<br />
pure, bright red. If treated well, it will bloom<br />
year-round.</td></tr>
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More correctly, the title of this post should read "why are the spathes of some species of <i>Anthurium</i> red?' - but that's way too wordy for a title. The fact of the matter is that there are some 1000 species of the genus <i>Anthurium</i>, and only a few species have red spathes.<br />
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The most commonly cultivated species is <i>Anthurium andreanum</i>, available in many different cultivars and hybrids. It is native to Ecuador and neighboring Columbia. Little is known about the species reproductive biology in the wild, but the bright red spathes literally scream "birds!" Well, not quite literally, but bright red colors in plants usually are an adaptation for attracting birds, either for pollination or fruit dispersal.<br />
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It has been speculated that the red to orange spathes in wild plants help birds find the ripe fruits, which they would eat, fly off, and thereby disperse the seeds. It's a common dispersal adaptation, found even in the most archaic of angiosperms (e.g. <i><a href="https://botanyprofessor.blogspot.com/2019/09/pitfalls-of-long-branch.html">Amborella</a></i>), and it may very well be true in this species, as well as many other species of <i>Anthurium</i>.<br />
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In all members of the Aroid family, flowers are tiny and crowded onto the elongate spadix. There have been many observations of pollination by tiny flies, beetles and other insects in various species of <i>Anthurium</i>, and it has been assumed that birds would take no notice of them. That was until recently.<br />
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A 2019 article by <a href="https://www.sciencedirect.com/science/article/pii/S0367253018304699">Bleiweiss et al.</a> provides the best evidence so far for bird-pollination in <i>Anthuriums</i> with red or other brightly colored spathes. It wasn't the first evidence of the possibility, as Bleiweiss cites a paper from some 20 years earlier by Kraemer and Schmitt making similar, if not as thorough, observations.<br />
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This reminded me of seeing nectar drops on an <i>Anthurium andreanum</i> specimen in the Bailey Hortorium greenhouse at Cornell, some 50 years ago, and wondering the same thing. That picture is posted below. You can see the nectar exuding from several of the tiny flowers. A patient hummingbird could get a decent meal by collecting a series of these droplets.<br />
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Makes me think about some other pollination mysteries ... stay tuned.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-FNVDi72q6Fg/Xnd_4sgZNQI/AAAAAAAAENw/Qa2BkZmZj-MVw6oXrR4bBatpM6d89QY6QCLcBGAsYHQ/s1600/Anthurium.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1328" data-original-width="916" height="640" src="https://1.bp.blogspot.com/-FNVDi72q6Fg/Xnd_4sgZNQI/AAAAAAAAENw/Qa2BkZmZj-MVw6oXrR4bBatpM6d89QY6QCLcBGAsYHQ/s640/Anthurium.JPG" width="440" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i>Anthurium andreanum</i> growing in a greenhouse at Cornell University around 1970. note the tiny droplets on some of the upper flowers (enlarged below).</td></tr>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglaC-sRzGJNv5TGV1By-rLom54ShtHeL4LKee9bYvOcnLdHjfDuby4Nak8nsn7ZH6nPebsbT6QJshv6jdz2qOs1Oo9qyYTw3GaBPHbD1D0H7067yBCjBJOzC8eJAX5dSJoDyGwg1WnLSq_/s1600/Anthurium+close.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="282" data-original-width="295" height="611" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglaC-sRzGJNv5TGV1By-rLom54ShtHeL4LKee9bYvOcnLdHjfDuby4Nak8nsn7ZH6nPebsbT6QJshv6jdz2qOs1Oo9qyYTw3GaBPHbD1D0H7067yBCjBJOzC8eJAX5dSJoDyGwg1WnLSq_/s640/Anthurium+close.jpg" width="640" /></a></div>
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Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com3tag:blogger.com,1999:blog-8570220338076553089.post-75291886616496556062020-03-13T12:12:00.000-07:002020-03-21T12:46:09.945-07:00Plant wrappers - leaf sheaths and bracts<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-ertwu7f3fgU/XmqaC43AUqI/AAAAAAAAELw/GcC9ecHdFsg_ceCUd-AWGQ2SY3vZSuB1wCLcBGAsYHQ/s1600/2005-04%2BLutz_023%2BMagnolia%2Bleaf%2Bsheath.JPG" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1024" data-original-width="1544" height="212" src="https://1.bp.blogspot.com/-ertwu7f3fgU/XmqaC43AUqI/AAAAAAAAELw/GcC9ecHdFsg_ceCUd-AWGQ2SY3vZSuB1wCLcBGAsYHQ/s320/2005-04%2BLutz_023%2BMagnolia%2Bleaf%2Bsheath.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">While the young leaves of <i>Magnolia</i><br />
are developing, they are each wrapped in a white<br />
bract (technically a specialized, bract-like stipule).<br />
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Leaves are the most plastic of all plant organs. That means that they can be modified in endless ways<br />
to result in a mind-boggling variety of shapes. Through evolution via adaptive modification, leaves form an endless array of light-gathering antennas, from the giant fronds of palms to the tiny scales of a juniper twig, but beyond that, have adapted into tendrils, insect-catching traps, and even the parts of the flower.<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-kjn-BoJJR4w/XmqaYG3iZoI/AAAAAAAAEL4/JzHAiH1AfSkcL4OLTvlmAk7B-b33U0wvwCLcBGAsYHQ/s1600/2005-03_22A%2BUSFBG%2BApiaceae%2Bsheath.JPG" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1544" data-original-width="1024" height="400" src="https://1.bp.blogspot.com/-kjn-BoJJR4w/XmqaYG3iZoI/AAAAAAAAEL4/JzHAiH1AfSkcL4OLTvlmAk7B-b33U0wvwCLcBGAsYHQ/s400/2005-03_22A%2BUSFBG%2BApiaceae%2Bsheath.JPG" width="265" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">In the fennel plant, the broad basal portions<br />
of the leaves, the leaf sheaths, overlap to protect<br />
the developing shoot apex.</td></tr>
</tbody></table>
Today, I'm talking about leaves, or parts of leaves, that form wrappers around tender growing parts of the shoot. Modified leaves that do so are called <b>bracts</b>, and the modified lower parts of leaves that do so are called <b>leaf sheaths</b>.<br />
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A bract is a whole leaf, though it is typically smaller than a regular leaf, simpler in shape, and often colored differently. In some cases, brightly colored bracts serve as part of the apparatus for attracting pollinators, and may even appear to be petals.<br />
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A leaf sheath, on the other hand, is the broad basal part of typically large, complex leaves that surrounds the growing tip of the shoot. The rest of the leaf - typically a petiole and a blade - is typically full-sized,<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-AkoKTkdLf5w/XmqfHNNcEzI/AAAAAAAAEME/jInP_Jzk1QIy1hZKyKVTDXQB1PnIkPS-QCLcBGAsYHQ/s1600/2007-01%2BCrocus%2B2.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1065" height="400" src="https://1.bp.blogspot.com/-AkoKTkdLf5w/XmqfHNNcEzI/AAAAAAAAEME/jInP_Jzk1QIy1hZKyKVTDXQB1PnIkPS-QCLcBGAsYHQ/s400/2007-01%2BCrocus%2B2.jpg" width="265" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">As flowers and leaves emerge from a <i>Crocus </i>corm<br />
in early spring, they are protected by white bracts.</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj75qzWBhvIXUoSpqnAi2BhA_u1HmBuIdu-oLXKYphHEXgZIiByi110yblkGPy0z6ck4fOUsHaW1MHNwQWa-KBlm4Un8dEINtNZJGzxPhYXIVeEB1lbcLtwX2_HJhkWXGwGNPhDsjlVoV50/s1600/12794+Bromeliaceae+USFBG+1996-11+%25282%2529.JPG" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1065" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj75qzWBhvIXUoSpqnAi2BhA_u1HmBuIdu-oLXKYphHEXgZIiByi110yblkGPy0z6ck4fOUsHaW1MHNwQWa-KBlm4Un8dEINtNZJGzxPhYXIVeEB1lbcLtwX2_HJhkWXGwGNPhDsjlVoV50/s400/12794+Bromeliaceae+USFBG+1996-11+%25282%2529.JPG" width="265" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">In this bromeliad, <i>Tillandsia cyanea,</i> a fan of colorful <br />
bracts help keep the plant on the radar of pollinators <br />
as the flowers emerge one at a time.</td></tr>
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-ChIa7Uumq5E/Xmqf8irAbPI/AAAAAAAAEMc/OWMmPi6MTaIo2lOUprjmqnc32ePZZ-idwCLcBGAsYHQ/s1600/15489%2BAphelandra%2BUSFBG%2B1984-07%2B.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1066" height="400" src="https://1.bp.blogspot.com/-ChIa7Uumq5E/Xmqf8irAbPI/AAAAAAAAEMc/OWMmPi6MTaIo2lOUprjmqnc32ePZZ-idwCLcBGAsYHQ/s400/15489%2BAphelandra%2BUSFBG%2B1984-07%2B.jpg" width="266" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i>Pachystachys lutea</i>, or yellow shrimp plant, forms<br />
a cone of yellow bracts to attract pollinators to<br />
the white flowers.</td></tr>
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As for leaf sheathes, some of the most spectacular are found in palms, but virtually all monocots form a leaf sheath when young. Leaf sheathes attach to the stem in a complete circle when young, but typically splits apart on one side as the leaf matures and the stem within it expands. In others, such as the royal palm, the overlapping leaf sheaths of the functioning leaves remain as a smooth, tight, crownshaft.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-63TijaIuLww/XmqhZl6Uz-I/AAAAAAAAEMw/FU-KSGpjiIgq1SJpDPXkMOMNCGWC19dXgCLcBGAsYHQ/s1600/Roystonea%2Bfrom%2BPalmpedia.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1166" data-original-width="1501" height="496" src="https://1.bp.blogspot.com/-63TijaIuLww/XmqhZl6Uz-I/AAAAAAAAEMw/FU-KSGpjiIgq1SJpDPXkMOMNCGWC19dXgCLcBGAsYHQ/s640/Roystonea%2Bfrom%2BPalmpedia.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The leaf sheathes of the royal palms (<i>Roystonea</i> spp.) can be more than four feet long. They remain intact as complete<br />
cylinders, forming what is called a crownshaft. Photo from Palmpedia, photographer not indicated.</td></tr>
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The "trunks" of banana plants are made up entirely of leaf sheaths, that may be more than three meters long, wrapped around each other (see <a href="http://botanyprofessor.blogspot.com/2012/05/invention-and-reinvention-of-trees.html">"The invention and reinvention of trees"</a>)<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQ0h10xZAM9BMq0iU3zKgJA0NHSbOjD71vFFGfUOLHGGGAs-sEXAPXRQmA96iodSTPTxtlpEI6IWFi0lFIA-rb9yPxZpFmA8WhXUhyphenhyphenii9ptp1p_JUvpT0yS56seJRwyin2DVYm9U5boq7S/s1600/Banana+plant.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="839" data-original-width="567" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQ0h10xZAM9BMq0iU3zKgJA0NHSbOjD71vFFGfUOLHGGGAs-sEXAPXRQmA96iodSTPTxtlpEI6IWFi0lFIA-rb9yPxZpFmA8WhXUhyphenhyphenii9ptp1p_JUvpT0yS56seJRwyin2DVYm9U5boq7S/s400/Banana+plant.jpg" width="270" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">As each new leaf emerges from the tip of the shoot<br />
of a banana plant, its sheath is longer than the previous<br />
ones. This builds up a pseudostem of overlapping,<br />
cylindrical leaf sheaths.</td></tr>
</tbody></table>
<br />
<br />
Recall from <a href="http://botanyprofessor.blogspot.com/2012/04/underground-plant-movement.html">"The underground plant movement"</a> that the bulb of an onion or amaryllis is also made up of leaf sheaths that fill up with food and water, and are left as storage organs as the leaf blade on top of them dries up and disappears.<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgddey0K2HQZMmfTIeu4qkzc7GgLL5899X9rskOL6LY9ebKK9LQ-o8qm1Sy4bNwgyUi8N7YYpStsbnjzDprbavXc3hyphenhyphen-IjqvE1rH-VLW1dkDd8Yw25hPS2tOcPHpLZBJHxaAjF2_1hNmT-9/s1600/2007-01+green+onion+cut.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1297" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgddey0K2HQZMmfTIeu4qkzc7GgLL5899X9rskOL6LY9ebKK9LQ-o8qm1Sy4bNwgyUi8N7YYpStsbnjzDprbavXc3hyphenhyphen-IjqvE1rH-VLW1dkDd8Yw25hPS2tOcPHpLZBJHxaAjF2_1hNmT-9/s400/2007-01+green+onion+cut.jpg" width="323" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">In a young onion plant, the leaf sheathes just above<br />
the roots begin to fill with food.</td></tr>
</tbody></table>
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-4V8tMlkQXHw/XmqidNQIaAI/AAAAAAAAENI/P1Nrv3wqixYSqPrTqC97USrPSfBoyHhAwCLcBGAsYHQ/s1600/2007-01%2BOnion%2Bcut.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1065" height="400" src="https://1.bp.blogspot.com/-4V8tMlkQXHw/XmqidNQIaAI/AAAAAAAAENI/P1Nrv3wqixYSqPrTqC97USrPSfBoyHhAwCLcBGAsYHQ/s400/2007-01%2BOnion%2Bcut.jpg" width="265" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">When the onion plant goes dormant for the<br />
season, the food-filled leaf sheathes remain,<br />
forming the rings of the onion. The<br />
outermost sheaths dry out to form a<br />
protective tunica.</td></tr>
</tbody></table>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5IxOGT7XWp8X1USONXXsSR0_Jl-7JYD9kSS8Ubq6ba63N3P8y4YOtxHCvxr7OKEoueHVUXKZFyw1i0U5QRMKl40j4F-y82KuNxwuQvq1kAtWhWX0D5IE8zKmwmqeHD3kChXspkaoDBrN2/s1600/2004-05-6+Iris+leaves.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1081" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5IxOGT7XWp8X1USONXXsSR0_Jl-7JYD9kSS8Ubq6ba63N3P8y4YOtxHCvxr7OKEoueHVUXKZFyw1i0U5QRMKl40j4F-y82KuNxwuQvq1kAtWhWX0D5IE8zKmwmqeHD3kChXspkaoDBrN2/s400/2004-05-6+Iris+leaves.jpg" width="270" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">In many irises, gladioli and other members of the<br />
Iridaceae, the leaf sheath is folded and the entire<br />
shoot looks like it has been pressed with a hot iron.<br />
Note that the newer leaves emerge from the<br />
overlapping, folded leaf sheathes.</td></tr>
</tbody></table>
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</div>
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Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com3tag:blogger.com,1999:blog-8570220338076553089.post-24893817680673731422019-12-06T10:59:00.000-08:002019-12-06T10:59:21.879-08:00Good fire, bad firesometimes seems that all wildfires are bad. Forests burn down, homes and whole towns are destroyed, carbon dioxide is released into the air, valuable wood is destroyed, and wild animals are killed or driven from their habitat..<br />
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So it is surprising to hear for the first time that wildfires are natural and necessary in many ecosystems. They become bad basically only because of our own interference.<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-jWlJNtxgGuA/XekUJ5oVbMI/AAAAAAAAEK4/xlPPrTreYXkJE_ul0tfEg1fJLRvryUsJQCLcBGAsYHQ/s1600/14408%2BBanksia%2Bcapsule.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="808" data-original-width="528" height="400" src="https://1.bp.blogspot.com/-jWlJNtxgGuA/XekUJ5oVbMI/AAAAAAAAEK4/xlPPrTreYXkJE_ul0tfEg1fJLRvryUsJQCLcBGAsYHQ/s400/14408%2BBanksia%2Bcapsule.jpg" width="261" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">As in many pines, the seed cones of <i>Banksia</i> in<br />
Australia, open only after a fire to release their<br />
seeds.</td></tr>
</tbody></table>
Ecosystems in which fires are a normal part of maintenance or renewal are those in which there are distinct wet seasons and dry seasons. During the wet season, there is abundant growth of trees, shrubs, grasses, and other herbs During the dry season, leaves and twigs fall from the woody plants and grasses dry out. Typically, this debris accumulates faster than it can decay, so builds up from year to year. Sooner or later a lightning strike will ignite the accumulated debris, causing a wildfire.<br />
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Burning removes the debris, releases nutrients back into the soil, clears out the undergrowth, trims dead branches from the trees. In some cases, shrubs are burnt to the ground, but re-sprout quickly at the beginning of the next wet season.<br />
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Plants in these areas are adapted to these periodic fires. Pine trees, for example, survive moderate fires, and require the ground to be cleared for seeds to germinate. In many species, seed cones will not even open until heated by fire. Where fires are prevented for a number of years, ground vegetation becomes thick and pines do not reproduce, and when fire inevitably strikes, it is more intense and trees die. For these reasons, foresters often conduct regular controlled burning to prevent more intense fires later.<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfXUC-EpvfNG7s4oRzlHBz-WgNPhvdorhj3ybwSP6jBt-mkvRStfaVctXvuP0sEXgnWrgxPqXJoA7xpEyRDI8CJDB17zreuI-90l9asveE81dPOw7cCyecK2_AtEUqhnN-vX7yvO74bofD/s1600/14734+Flatwoods+after+fire.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1072" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfXUC-EpvfNG7s4oRzlHBz-WgNPhvdorhj3ybwSP6jBt-mkvRStfaVctXvuP0sEXgnWrgxPqXJoA7xpEyRDI8CJDB17zreuI-90l9asveE81dPOw7cCyecK2_AtEUqhnN-vX7yvO74bofD/s640/14734+Flatwoods+after+fire.jpg" width="427" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">In the pine flatwoods of Florida, fires remove the <span style="font-size: 12.8px;">undergrowth</span><span style="font-size: 12.8px;"> and debris, </span><span style="font-size: 12.8px;">clearing the way for </span><br />
<span style="font-size: 12.8px;">germination and growth of pine seedlings. </span><span style="font-size: 12.8px;">Without fires, pines </span><span style="font-size: 12.8px;">would gradually disappear. </span><br />
<span style="font-size: 12.8px;">Their thick bark protects the trunks, and the upper </span><span style="font-size: 12.8px;">branches are spared as well, as long as fires </span><br />
<span style="font-size: 12.8px;">are frequent and not too intense. </span><span style="font-size: 12.8px;">Saw </span><span style="font-size: 12.8px;">palmettos, </span><i style="font-size: 12.8px;">Serenoa repens</i><span style="font-size: 12.8px;">, cover much of the </span><span style="font-size: 12.8px;">ground </span><br />
<span style="font-size: 12.8px;">here, but can be </span><span style="font-size: 12.8px;">seen here recovering quickly after </span><span style="font-size: 12.8px;">a fire. </span></td></tr>
</tbody></table>
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhe6mBjm0kur-xgJmqp_nO92nctbsaZg63aROc77Jq-AqSYheB2Byp_eSaDZ0-t6tiztjft4ZqcvkH9trOTIk4XJQzKooxnS9KUpSa1ukDtVJiTyJrFedq86xO6ivpCFKXfh5Y4oxZY0snW/s1600/15113+Lilium+catesbyii+Flatwoods+Park+1999-10.JPG" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1065" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhe6mBjm0kur-xgJmqp_nO92nctbsaZg63aROc77Jq-AqSYheB2Byp_eSaDZ0-t6tiztjft4ZqcvkH9trOTIk4XJQzKooxnS9KUpSa1ukDtVJiTyJrFedq86xO6ivpCFKXfh5Y4oxZY0snW/s400/15113+Lilium+catesbyii+Flatwoods+Park+1999-10.JPG" width="265" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Bulb plants, like this Florida native <i>Lilium catesbaei</i>, <br />
survive fires below ground. Plants that sit out <br />
the dry fire season are particularly common in<br />
California, South Africa, and Australia.</td></tr>
</tbody></table>
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The California chaparral and other forms of Mediterranean vegetation are adapted to winter rains and long summer droughts, and are also fire-maintained. It is here where we see shrubs well-adapted for re-sprouting after burning to the ground. Grasses, and wildflowers also thrive after fires, and are suppressed if the shrubby overgrowth becomes too thick. Between the pine forests and the chaparral, much of California is thus prone to natural fires, setting up an unfortunate conflict between nature and people building homes on vegetated hillsides. The same tragic conflict can be seen in many parts of Australia and southern Africa.<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-pCmYV56huAo/Xel4fQvg78I/AAAAAAAAELE/buA2t6lqNMMv5CnQh0gm4NVWHunj_d2GQCLcBGAsYHQ/s1600/15126%2BLiatris.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1044" height="400" src="https://1.bp.blogspot.com/-pCmYV56huAo/Xel4fQvg78I/AAAAAAAAELE/buA2t6lqNMMv5CnQh0gm4NVWHunj_d2GQCLcBGAsYHQ/s400/15126%2BLiatris.jpg" width="260" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Wildflowers, such as this <i>Liatris</i>, flourish where<br />
fires are frequent in Florida.</td></tr>
</tbody></table>
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The only places where wildfires are rare are in areas with reliable, year-round rainfall, or in areas of practically no rainfall. So rain forests, temperate deciduous forests, and deserts do not normally experience fires. In the rain forest, and temperate forests with precipitation all year long, vegetation rarely dries out, and debris is decomposed quickly. In the deserts, vegetation is sparse, and very little debris is produced. It's the areas between these extremes that rely on fires. Aside from the chaparral and pine forests mentioned above, this would include the grasslands and deciduous tropical forests that cover vast areas of Africa and tropical America.<br />
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So how do we humans turn good fires into bad fires? There are several ways.<br />
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First, by overzealous prevention of fires where fires should normally be occurring, we allow more debris to build up, allow opportunistic undergrowth vegetation to run rampant, setting up for a more disastrous fire when lightning eventually strikes. In these disastrous fires, pines are not only pruned, but burned to the ground. Such fires may be so hot that even the root systems of normally resilient shrubs are destroyed, and then do not re-sprout.<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-bkSZFWBXrbo/XekSHow1BII/AAAAAAAAEKs/gEj8GeTw-dEJ2Jr14w4Ufd_lumwKdxliQCLcBGAsYHQ/s1600/11986%2BYellowstone%2Bfire%2B%2BEpilobium%2BWyoming%2B1989-08%2B%252813%2529.JPG" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1065" data-original-width="1600" height="424" src="https://1.bp.blogspot.com/-bkSZFWBXrbo/XekSHow1BII/AAAAAAAAEKs/gEj8GeTw-dEJ2Jr14w4Ufd_lumwKdxliQCLcBGAsYHQ/s640/11986%2BYellowstone%2Bfire%2B%2BEpilobium%2BWyoming%2B1989-08%2B%252813%2529.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">After the big fire in Yellowstone National Park in 1989, grasses and <span style="font-size: 12.8px;">wildflowers, such as the pink fireweed, </span><i style="font-size: 12.8px;">Epilobium angustifolium</i><span style="font-size: 12.8px;">, </span><span style="font-size: 12.8px;">grow abundantly, a boon to local herbivores. </span></td></tr>
</tbody></table>
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Second, climate change is resulting in the expansion of dry seasons into formerly wet forests in many parts of the world. The intensity of droughts, as well as floods, hurricanes, and blizzards is increasing. This is not currently seen as a significant factor in the catastrophic fires in the Amazon Basin, but are a factor in the desertification of the African savannas.<br />
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Third, clearing and burning of forest for conversion to farm or grazing land, which is occurring in the Amazon Basin at an increasing rate, can get out of hand during dry periods and burn more extensive areas than normal. Fires are normal only where rain forest transitions into deciduous tropical forest, mostly along the southern fringe of the Amazon forest. Clearing of the forest, apparently supported by the current government, is also fragmenting the forest, causing it to get drier and less able to sustain itself.<br />
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So the burning of the Amazon rain forest, unlike the routine burning of the chaparral and pine forests, is a tragically bad fire. It is resulting in a significant loss of biodiversity and loss of photosynthetic activity that could help offset climate change.<br />
<div class="separator" style="clear: both; text-align: center;">
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://cdn1.spiegel.de/images/image-1461920-860_poster_16x9-uajm-1461920.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img alt="Rauch steigt in Brasilien auf - die Feuer haben sich in den vergangenen Tagen ausgebreitet" border="0" height="360" src="https://cdn1.spiegel.de/images/image-1461920-860_poster_16x9-uajm-1461920.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: right;"><div style="text-align: left;">
<span style="font-family: "times" , "times new roman" , serif; font-size: xx-small;"><span style="background-color: white;"><span style="font-size: x-small;">The fires in the Amazon Basin are largely due to human activity. They are a tragedy because of the huge loss of biodiversity, release of CO</span><span style="font-size: xx-small;">2</span><span style="font-size: x-small;"> into the atmosphere, and loss of photosynthetic oxygen replenishment. </span></span></span></div>
<span style="font-family: "times" , "times new roman" , serif; font-size: x-small;"><span style="background-color: white;">AFP PHOTO / GREENPEACE / VICTOR MORIYAMA</span></span></td></tr>
</tbody></table>
Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com1tag:blogger.com,1999:blog-8570220338076553089.post-63237296725439505922019-09-25T10:12:00.001-07:002019-10-01T13:43:33.616-07:00Pitfalls of the long branchLong branches in phylogenetic trees represent lineages of organisms that have been around for a long time, but exist today as only one or a few species. A few years ago, I discussed two examples in detail: the monocot genus, <i><a href="http://botanyprofessor.blogspot.com/2013/04/whats-so-primitive-about-acorus.html">Acorus</a></i>, and the archaic angiosperm species <i><a href="http://botanyprofessor.blogspot.com/2014/07/whats-so-primitive-about-amborella.html">Amborella trichopoda</a>.</i> I feel that the topic is worthy of a review, especially for newer readers who may not have gone back to the older posts. <br />
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In both cases, these lineages branched off very early, over 100 million years ago, but have left no fossils, and have no close living relatives. The <i>Amborella </i>branch is the earliest surviving lineage of angiosperms in general, while the <i>Acorus</i> branch is the earliest surviving lineage of monocots. Expressed in a different way, <i>Amborella</i> is the sister group to all other angiosperms, and <i>Acorus</i> is the sister group to all other monocots.<br />
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At the level of phylogenetic analysis, such long branches have often been problematical, with "long branch attraction" leading occasionally to errors in the resulting phylogenetic tree. This has been much discussed, and there are ways to correct for it, but this is a very technical issue. If you want to learn more, you might begin with . Begin with this <a href="https://en.wikipedia.org/wiki/Long_branch_attraction">Wikipedia article</a>, and go from there.<br />
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In both cases, however, many phylogenetic analyses have confirmed the ancient position, and length of these two branches, so that is not a question here..<br />
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Such long branches can lead to errors of interpretation at another level, however. A common misconception is that what we see in the current species, which occupy the very tips of these ancient lineages, will be similar to the ancestors from which the lineage began, i.e. that these are archaic or primitive species.<br />
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But think about it. These lineages have been around for more than 100 million years (140 million for <i>Amborella</i>, 120 million for <i>Acorus</i>). Isn't it likely that the occupants of these lineages have changed somewhat over all those years?<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-OmbGXxk2dAU/XYJRrsUopRI/AAAAAAAAEIE/x2Y2xRoCSv09llr5AMuhLi2QZN0NYOcKgCLcBGAsYHQ/s1600/Amborella%2Bfruits%2BJoel%2BMcNeal.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="800" data-original-width="600" height="400" src="https://1.bp.blogspot.com/-OmbGXxk2dAU/XYJRrsUopRI/AAAAAAAAEIE/x2Y2xRoCSv09llr5AMuhLi2QZN0NYOcKgCLcBGAsYHQ/s400/Amborella%2Bfruits%2BJoel%2BMcNeal.jpg" width="300" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i>Amborella</i> fruits are single-seeded drupes, adapted for<br />
dispersal by fruit-eating birds. This is a specialization<br />
that has <span style="font-size: 12.8px;">evolved many times among angiosperms, including</span><br />
most famously, cherries. <span style="font-size: 12.8px;">Early angiosperms most</span><br />
<span style="font-size: 12.8px;">likely had fruits that split open to release several to many</span><br />
<span style="font-size: 12.8px;">seeds (see <a href="http://botanyprofessor.blogspot.com/2014/08/were-first-carpels-plicate-or-ascidiate.html">Were the first carpels plicate or ascidiate? </a>. </span><br />
<span style="font-size: 12.8px;">Small, unisexual flowers in dense </span><span style="font-size: 12.8px;">clusters</span><br />
<span style="font-size: 12.8px;"> is </span><span style="font-size: 12.8px;">also a specialization. </span><span style="font-size: 12.8px;">Photo courtesy Joel McNeal.</span></td></tr>
</tbody></table>
Modern phylogenetic analyses are based primarily on molecular (DNA) comparisons, so in-and-of themselves tell us nothing about changes in the characteristics of the plants occupying the lineages. So there is no direct basis for inferring what the first species in a lineage looked like or in what ways their modern descendants may have changed.<br />
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As I argued in the previous posts, both <i>Acorus </i>and <i>Amborella</i>, as they exist today, exhibit a mix of ancient and specialized characteristics. They are both well-adapted to their environments, and have some distinctive specialized characteristics, particularly in their adaptations for pollination and seed dispersal. The<i> Acorus</i> and <i>Amborella </i>lineages have been around for such a long time, that it is rather absurd to think that they have not changed at all during that time. For groups that have good fossil records, we can trace such changes. Fossils, for example, tell us that we modern humans have changed a great deal from the first members of our genus, even more from the ancestral genus <i>Australopithecus</i>!<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTHrh_u5ql3IQBjEQFMX-HgqU-q7T9twZmD9RQ_PmVWq4HoWJA8T30yERw2Tr9QFJyehV9RvTT3LoeSG-CdQxyuBdlzDUFvnLmRCloWnom23u0phelVQfTINvCL605Cr2wg9T6nu8a7AZc/s1600/Acorus_calamus_by+H+Zell%252C+Wikimedia+Commons.JPG" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1200" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiTHrh_u5ql3IQBjEQFMX-HgqU-q7T9twZmD9RQ_PmVWq4HoWJA8T30yERw2Tr9QFJyehV9RvTT3LoeSG-CdQxyuBdlzDUFvnLmRCloWnom23u0phelVQfTINvCL605Cr2wg9T6nu8a7AZc/s400/Acorus_calamus_by+H+Zell%252C+Wikimedia+Commons.JPG" width="298" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The spadix-like inflorescence of <i>Acorus</i> led early<br />
taxonomists to classify this genus with the Aroids.<br />
Since the two<span style="font-size: 12.8px;"> families are not closely related, it is likely </span><br />
<span style="font-size: 12.8px;">that </span><span style="font-size: 12.8px;">the similarity is due to convergent evolution, driven by</span><br />
adaptations for pollination. A spadix is a highly specialized<br />
way <span style="font-size: 12.8px;">to arrange flowers and has evolved independently in a</span><br />
number of families, including the Aroid, Palm, <span style="font-size: 12.8px;">and </span><br />
<span style="font-size: 12.8px;"><i>Cyclanthus</i> families. It is likely that the early monocots had</span><br />
looser arrangements of flowers, more like those in most<br />
Alismatales, and that dense flower spikes were not<br />
characteristic of the first members of the lineage.<br />
The folded and fused (equitant) leaves of <i>Acorus</i>, are<br />
also <span style="font-size: 12.8px;">a specialized adaptation that has occurred in many</span><br />
unrelated families, most famously in several members<br />
of the Iris Family.</td></tr>
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How do we know, or at least develop hypotheses, as to what changes have taken place in a lineage in the absence of any fossils? We can look at the characteristics of other early branches to see what they have in common, and hypothesize that the shared characteristics were present in their common ancestor.<br />
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We can also analyze how particular characteristics might have arisen as adaptations to natural selective pressures, and determine which are most likely ancestral, and which are more specialized. Adaptations arise in logical sequences and often become canalized in non-reversible directions (see <a href="http://botanyprofessor.blogspot.com/2015/10/what-is-adaptation.html">What is an adaptation?</a> and <a href="http://botanyprofessor.blogspot.com/2014/07/g-l-stebbins-and-process-of-adaptive.html">G. L. Stebbins and the process of adaptive modification</a>)<br />
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Both in comparison with other related groups, and in considering likely sequences of adaptations, <i>Amborella</i> and <i>Acorus </i>are specialized in some ways. For<i> Amborella</i>, small, numerous, unisexual flowers in clusters, and red, single-seeded fruits are both features that are more specialized than in other archaic angiosperms. For <i>Acorus</i>, the dense spikes of flowers with fused carpels (<a href="http://botanyprofessor.blogspot.com/2014/08/were-first-monocots-syncarpous.html">see also Were the first moncots syncarpous?</a>) and the the leaves with the two sides fused together (equitqnt are specialized features, that have evolved independently in a number of families from more generalized types.<br />
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Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com2tag:blogger.com,1999:blog-8570220338076553089.post-34527169876260834692019-09-18T06:23:00.000-07:002019-09-25T08:21:22.517-07:00Guide to the mosses of central FloridaI have spent much time in the past few years studying the mosses of central Florida and posting portraits of the common species. This work has culminated in a Guide and Interactive key, which has now been posted as part of the <a href="https://florida.plantatlas.usf.edu/">Atlas of Florida Plants</a>..You can find the link on the Atlas home page, in the right column.<br />
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The guide is in pdf format, so no special software is needed to use the key. Though it can be printed<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-9P79DcXXTKM/XYuEueDJn5I/AAAAAAAAEIQ/Fu78CydfHPoxpqVLq1g6m4arX4URfMzrACLcBGAsYHQ/s1600/page%2B1%2Bof%2Bkey.JPG" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="670" data-original-width="599" height="400" src="https://1.bp.blogspot.com/-9P79DcXXTKM/XYuEueDJn5I/AAAAAAAAEIQ/Fu78CydfHPoxpqVLq1g6m4arX4URfMzrACLcBGAsYHQ/s400/page%2B1%2Bof%2Bkey.JPG" width="357" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Page 1 of the key, showing the three initial choices. Move<br />through the key by clicking on arrows. One can also go<br />directly to the index by clicking the box in the upper right.<br /></td></tr>
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out, it is designed to be used on-line, or off-line with computer or cell phone, as there are active links leading the user from one part of the guide to another.<br />
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The key leads to species profile pages, similar to the postings I have done on this blog site, but briefer. Currently, the guide covers 59 common mosses of central Florida, but as stated in the introduction, it is a work in progress. The index at the back of the guide includes all species reported as occurring in Florida, and as we are able to include additional species, the guide potentially will morph into one that covers the entire state. The guide will therefore be periodically upgraded and reposted. Those of you who have been following the moss posts are encouraged to notify me of any errors you see in the key, any information or photos of additional species, or any other suggestions.<br />
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Thanks for your interest and support.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-zwBrMlVBcyY/XYIpjiz9BwI/AAAAAAAAEH4/zyfZcZIyKo8vH3LnCRWlBEAolo_7N7NDgCLcBGAsYHQ/s1600/Sphagnum%2Bspecies%2Bprofile.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="681" data-original-width="627" height="640" src="https://1.bp.blogspot.com/-zwBrMlVBcyY/XYIpjiz9BwI/AAAAAAAAEH4/zyfZcZIyKo8vH3LnCRWlBEAolo_7N7NDgCLcBGAsYHQ/s640/Sphagnum%2Bspecies%2Bprofile.jpg" width="587" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">On the species profile pages, one can find photographs, maps of distribution, and a link to the species page in the Atlas (logo under the map). One can also go to the index to see what other species are reported from Florida, or return to the key.</td></tr>
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<br />Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com1tag:blogger.com,1999:blog-8570220338076553089.post-26230920692503382832019-04-19T14:07:00.001-07:002022-04-26T09:34:19.270-07:00Theme and Variation - the Amaryllidaceae<div class="separator" style="clear: both; text-align: center;">
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<tr><td class="tr-caption" style="text-align: center;"><div style="font-size: 12.8px;">
The primary types of cultivated amaryllis are in the <span style="font-size: 12.8px;">genus </span><i style="font-size: 12.8px;">Hippeastrum</i><span style="font-size: 12.8px;">. </span></div>
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<span style="font-size: 12.8px;">Their flowers are mostly </span><span style="font-size: 12.8px;">shades and mixes of red, pink, and white. </span></div>
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<span style="font-size: 12.8px;">This is one of my favorite cultivars, "Eye-catcher."</span></div>
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This spring, while I was waiting eagerly for the amaryllis plants in my yard to bloom, I started reflecting on <br />
the marvelous family to which they belong, and how nicely they represent a fascinating aspect of plant evolution.<br />
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The Amaryllis family is known and beloved worldwide, even by people unfamiliar with its technical name or taxonomy, for it provides us with a variety of unique spring-flowering bulbs and perennials, from daffodils to subtropical amaryllis and tropical <i>Crinums</i>.<br />
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As presently defined, Amaryllis (technically the genus <i>Hippeastrum</i>), daffodils (<i>Narcissus</i>) and <i>Crinum</i> all belong to the subfamily Amarylliodeae. Onion, garlic, etc.are also members of the family, constituting the subfamily Allioideae. Finally, the blue-flowered "Lily-of-the-Nile" (<i>Agapanthus)</i>, from southern Africa, is technically in it's own subfamily, Agapanthoideae. Altogether, there are some 1600 species in 75 genera, found naturally on every unfrozen continent.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkkEsV5c0P8qn8SP1QfXwWCU3kH_tAUqnd5Rw0OAIxShqGFFFqq3OZRbRTmXiV3NX1fvHXSo_VhR95VKTCZsX-QXudoKDiWdJ3tf7Dn93I7JlOfCOFTESqIafmamFXX0NEMAchIvaB5k-U/s1600/2006+-+spring+024+Connecticut+daffodils+%25282%2529.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="855" data-original-width="1600" height="340" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkkEsV5c0P8qn8SP1QfXwWCU3kH_tAUqnd5Rw0OAIxShqGFFFqq3OZRbRTmXiV3NX1fvHXSo_VhR95VKTCZsX-QXudoKDiWdJ3tf7Dn93I7JlOfCOFTESqIafmamFXX0NEMAchIvaB5k-U/s640/2006+-+spring+024+Connecticut+daffodils+%25282%2529.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Daffodils are specialized members of the genus <i>Narcissus</i>, in which the umbel has been reduced to a single flower.</td></tr>
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<tr><td class="tr-caption" style="text-align: center;">The subfamily Agapanthoideae consists of the single genus <i>Agapanthus </i>from<br />
southern Africa. Flowers are blue to white.</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaxoitWXMzaBlAtRsoNZQ4Ixcl0g0jPIEXm87asIAHvEL4gfZPAIrog9_9OEJiSI5W7qNhKGaLr4akb6K5M-Ww8_GEXYxOVDx1ADbtMflnLj149aHQ6nxn7gR8ngeI1YqB4-Fj4TuOnax6/s1600/2006-05-England+028+Onion.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1065" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhaxoitWXMzaBlAtRsoNZQ4Ixcl0g0jPIEXm87asIAHvEL4gfZPAIrog9_9OEJiSI5W7qNhKGaLr4akb6K5M-Ww8_GEXYxOVDx1ADbtMflnLj149aHQ6nxn7gR8ngeI1YqB4-Fj4TuOnax6/s640/2006-05-England+028+Onion.jpg" width="424" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The onion subfamily, Allioideae, contains numerous aromatic and edible species.<br />
The characteristic pungent fragrances are based on allyl sulfides,<br />
which in nature act as deterrents to insect pests.</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBt92631RlmBbgprQ2SYkerNRa5_1p6NOVvwm-W9h0JMLMhTNeAsi6vH_rnfkN-h1UyGum3759kyAWIIflhyphenhyphenwcfrIRLhv8Ri4RyRu4leAIzejPs8odBv5cEVm0LDxsXQBZzE-efEeACJML/s1600/Red_onion_cross_section_Wiki+by+Amada44.jpg" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1511" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBt92631RlmBbgprQ2SYkerNRa5_1p6NOVvwm-W9h0JMLMhTNeAsi6vH_rnfkN-h1UyGum3759kyAWIIflhyphenhyphenwcfrIRLhv8Ri4RyRu4leAIzejPs8odBv5cEVm0LDxsXQBZzE-efEeACJML/s320/Red_onion_cross_section_Wiki+by+Amada44.jpg" width="302" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The true bulbs of onions and amaryllis are made up of<br />
the swollen bases of recent leaves that encircle the<br />
central stem. The outermost layers, representing<br />
older leaf bases, become dried and paper-like,<br />
which protects the fresh inner layers from drying out.<br />
This gives rise to the designation "tunicate bulbs,"<br />
differing from the scale-bulbs of the true lilies.<br />
Photo by Amada44, CC BY-SA 3.0.</td></tr>
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So what defines this family? What is the common theme upon which the 1600 species are variants? The vast majority of the species in this family are geophytes, plants that survive adverse seasons underground. Most species form bulbs, but some, like <i>Agapanthus</i> and certain members of the Allioideae, employ underground rhizomes instead. The leaves are strap-shaped (sometimes tubular and hollow in the onions) and extend themselves upward from the bulb by basal intercalary meristems (see "<a href="https://botanyprofessor.blogspot.com/2012/01/how-grass-leaf-got-its-stripes.html">How the grass leaf got its stripes"</a>). This is the most common form of leaf in the monocots, and it varies little in this family.</div>
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True, or tunicate bulbs (see illustration to the left), differing from the scale-bulbs of the true lilies, do seem to be a unique invention of this family, though some members of the Lily family, such as tulips, have evolved a similar type of bulb independently.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-6bWnVZJAbAQ/XLh51NZ-8gI/AAAAAAAAEFc/Pnfk2bOgkqAtGd4U-dAnL61Mk0KZhKeQwCLcBGAs/s1600/20190417_074237.jpg" style="clear: right; display: inline; margin-bottom: 1em; margin-left: auto; margin-right: auto; text-align: center;"><img border="0" data-original-height="1600" data-original-width="1200" height="400" src="https://1.bp.blogspot.com/-6bWnVZJAbAQ/XLh51NZ-8gI/AAAAAAAAEFc/Pnfk2bOgkqAtGd4U-dAnL61Mk0KZhKeQwCLcBGAs/s400/20190417_074237.jpg" width="300" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><div style="font-size: medium; text-align: start;">
<span style="font-size: 12.8px; text-align: center;">Flowers in the Amaryllidaceae undergo preliminary </span><br />
<span style="font-size: 12.8px; text-align: center;">development below </span><span style="font-size: 12.8px;">ground, between leaves or within the </span><br />
<span style="font-size: 12.8px;">bulb and are protected </span><span style="font-size: 12.8px;">by a closed sheath. The enclosed </span><br />
<span style="font-size: 12.8px;">bud is then pushed upward by </span><span style="font-size: 12.8px;">the intercalary growth of </span><br />
<span style="font-size: 12.8px;">the stalk.</span></div>
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But it is how the flowers emerge from the bulbs that is the most iconic, revolutionary, and consistent theme of the family. Flowers form below ground, tightly enveloped in a protective sheath. Below each inflorescence bud, a stalk (the <b>peduncle</b>) develops and lengthens through <b>basal intercalary growth</b> (i.e. new tissues are produced at the base of the stalk, pushing older tissues and the inflorescence bud upwards). After rising to optimum height for pollination and eventual seed dispersal, the sheath splits open to reveal a simple <b>umbel</b>, i.e. one to many flowers arising from a single point at the tip of the stalk, roughly forming the shape of an umbrella or sometimes an entire sphere.<br />
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This proved to be a remarkably effective way to protect and elevate the flowers, for after it evolved in the common ancestors of the family, descendant species spread worldwide, adapting to different climates, soils, and pollinators. Such a spreading diversification is called an <b>adaptive radiation</b>. Note that the special structure and growth form of the inflorescence remained essentially unchanged throughout the family, while details of flower structure and color, fruit type, and physiological adaptations diversified.<br />
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-PVvyRqHE1ZA/XLZC47xEWQI/AAAAAAAAEE4/Clvak1fEPpIMltPT6vULIK1QZWGqKGMuwCEwYBhgL/s1600/Lycoris_aurea_Wiki%2Bby%2BTomago%2BMoffle.jpg" style="clear: left; display: inline; margin-bottom: 1em; margin-left: auto; margin-right: auto; text-align: center;"><img border="0" data-original-height="576" data-original-width="632" height="363" src="https://2.bp.blogspot.com/-PVvyRqHE1ZA/XLZC47xEWQI/AAAAAAAAEE4/Clvak1fEPpIMltPT6vULIK1QZWGqKGMuwCEwYBhgL/s400/Lycoris_aurea_Wiki%2Bby%2BTomago%2BMoffle.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Yellow flowers are uncommon in the Amaryllidaceae, but found here in<br />
<i>Lycoris aureus</i>. Photo by Tomago Moffle, CC BY-SA 3.0.</td></tr>
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The importance of this discussion is not simply to say how wonderful and unique the Amaryllidaceae is, but to stimulate us, particularly those of us who are teachers, to look for similar patterns of breakthrough adaptations followed by adaptive radiation throughout the plant kingdom.<br />
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Almost any genus, and sometimes a whole family can be seen to be based on some "great idea," i.e. some new structure, growth pattern, flower type, etc., that gave the ancestral species an advantage and allowed its descendants to diversify into great numbers. Two simple examples are the genus <i>Aquilegia</i> (columbines) with its nectar spurs arising from each of the five petals, and the genus <i>Euphorbia</i>, with its highly compact flowering units called cyathia.<br />
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How many examples can you find? Can you explain the adaptive value of the distinctive features?<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-ANWt81lyOCg/XLo3tFL7iPI/AAAAAAAAEGE/gLWAkBqdGlsU3b3QeUx7U590faum0AgOACEwYBhgL/s1600/2003-12-11%2BPoinsettia.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1081" data-original-width="1600" height="216" src="https://4.bp.blogspot.com/-ANWt81lyOCg/XLo3tFL7iPI/AAAAAAAAEGE/gLWAkBqdGlsU3b3QeUx7U590faum0AgOACEwYBhgL/s320/2003-12-11%2BPoinsettia.jpg" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Each yellowish, red-tipped structure in this Poinsettia <br />
(genus <i>Euphorbia</i>) is a cyathium, a cupule containing several<br />
tiny flowers.</td></tr>
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-M9nkxFBMxFM/XLo26pDtxtI/AAAAAAAAEF8/43u_QV4TZ6gku_65XOJP2B7XXFxlR2-pwCLcBGAs/s1600/09857%2BAquilegia%2Byellow.JPG" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1234" data-original-width="1600" height="246" src="https://4.bp.blogspot.com/-M9nkxFBMxFM/XLo26pDtxtI/AAAAAAAAEF8/43u_QV4TZ6gku_65XOJP2B7XXFxlR2-pwCLcBGAs/s320/09857%2BAquilegia%2Byellow.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The highly distinctive flowers of <i>Aquilegia</i> feature a nectar<br />
spur projecting backwards from each petal.</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhE85udXSxaYeMQoyz-xXFhBSrF2nF_e5sKbgJjyv57JWW4O4kcxv1pqPR9aMfoy_aUA0irjqIWUP5RCKkyW2zLH9OZsHA5nTpSsO-r17cED_4aBNqn6OoKS2lU_iHgCWLAYRfyTSOxJeV/s1600/20190417_131443+%25282%2529.jpg" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="1275" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhE85udXSxaYeMQoyz-xXFhBSrF2nF_e5sKbgJjyv57JWW4O4kcxv1pqPR9aMfoy_aUA0irjqIWUP5RCKkyW2zLH9OZsHA5nTpSsO-r17cED_4aBNqn6OoKS2lU_iHgCWLAYRfyTSOxJeV/s640/20190417_131443+%25282%2529.jpg" width="507" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The giant crinum, <i>C. asiaticum</i>, from southern China, is a tropical evergreen<br />
plant that develops a pseudostem, similar to that of the banana, made of the<br />
tubular bases of the leaves.</td></tr>
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Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com1tag:blogger.com,1999:blog-8570220338076553089.post-9407152075946877392019-03-27T14:53:00.000-07:002019-03-27T14:53:20.143-07:00Mosses of Central Florida 52. Gemmabryum apiculatum<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4qyK8gNzpb26nfDfbKUq6HUHgmX9uDqSWX5b2iYZ0B0EUCdfyrfA3TheMQThh4toYkq-bAJO8NufJWGPuSB1CI16ysCfyATYGZogt3p-rBIKAq-xACVHTtKJBGy1DNUy2-L74w6yuv_p6/s1600/Gemmabryum+apiculatum.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="499" data-original-width="750" height="265" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4qyK8gNzpb26nfDfbKUq6HUHgmX9uDqSWX5b2iYZ0B0EUCdfyrfA3TheMQThh4toYkq-bAJO8NufJWGPuSB1CI16ysCfyATYGZogt3p-rBIKAq-xACVHTtKJBGy1DNUy2-L74w6yuv_p6/s400/Gemmabryum+apiculatum.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i>Gemmabrum apiculatum</i> forms thick cushions, with well-spaced leaves on<br />the shoots.</td></tr>
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<i>Gemmabryum apiculatum</i> (Schwagrichen) J. R. Spence & H. P. Ramsay (Bryaceae) forms colonies of tiny, upright leafy shoots on damp soil in shady areas. Leaves are long-ovate, well-spaced along the stems, and mostly 1 mm or more in length. Leaf cells are narrower than in related species, 6 to 8 times longer than wide, and become square toward the base.<br />
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The species characteristically forms tiny reproductive tubers or bulbils along the rhizoids in the soil or in the axils of the leaves. Bulbils are brown, pear-shaped, and 40-80 µm long. I have not yet seen spore capsules in our area.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiq1esgirtsWkTZRZflnRj4LCSrCFAqlk06XCWBk2yvyXfOskzrmivGJHLs27mACSPJfPO3ayzOnJ1e3cWd64XM6KdoaskUX_uYSPZl-WrltRxrOP6QxMf_H11mZ8tWyUyu8KTZYNWPTOOH/s1600/Gemmabryum+apiculatum2.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="499" data-original-width="750" height="265" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiq1esgirtsWkTZRZflnRj4LCSrCFAqlk06XCWBk2yvyXfOskzrmivGJHLs27mACSPJfPO3ayzOnJ1e3cWd64XM6KdoaskUX_uYSPZl-WrltRxrOP6QxMf_H11mZ8tWyUyu8KTZYNWPTOOH/s400/Gemmabryum+apiculatum2.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Brown, pear-shaped bulbils in the leaf axils are characteristic of <br /><i>Gemmabryum apiculatum. </i>Photo by Ainun Nadhifah</td></tr>
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<i>Gemmabryum apiculatum </i>is probably to be found throughout the state, as it is found in coastal regions of other southeastern states, though our documented specimens are from central Florida southward. It is also found widely in the tropics. <br />
<i>G. coronatum</i> has a similar distribution, with some reports from the north. The leaves tend to be rolled at the margins, and the leave cells are shorter, 3-4 times as long as wide.<br />
A third species, <i>G. exile</i>, has been reported only from Collier County, but is easily recognized by its stringy stems and small, folded leaves.<br />
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<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-BFa9zirppVU/XJvqvuWtpTI/AAAAAAAAEEI/xyTJ3v8zc-EWNxs2w5r64l_hrDR8021DQCLcBGAs/s1600/Gemmabryum%2Bapiculatum3.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="654" data-original-width="600" height="400" src="https://4.bp.blogspot.com/-BFa9zirppVU/XJvqvuWtpTI/AAAAAAAAEEI/xyTJ3v8zc-EWNxs2w5r64l_hrDR8021DQCLcBGAs/s400/Gemmabryum%2Bapiculatum3.jpg" width="366" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The leaf of <i>Gemmabryum apiculatum</i> features a strong<br /> midrib, and elongate cells that become squarish toward the base, <br />Photo by Ainun Nadhifah</td></tr>
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<br />Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-89388401996322713922019-03-06T08:35:00.001-08:002019-03-06T08:36:25.712-08:00Mosses of Central Florida 15. Physcomitrium pyriforme<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-HzIqbP18mhI/Vxe52xIBqWI/AAAAAAAACrw/tWa9nurnFI8E3enjGEeTbadqicHjGQawwCLcB/s1600/Physcomitrium%2B3%2Bfrom%2Bpond%2Bedge%2Bby%2BLSA%2B2009-02-19.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="265" src="https://1.bp.blogspot.com/-HzIqbP18mhI/Vxe52xIBqWI/AAAAAAAACrw/tWa9nurnFI8E3enjGEeTbadqicHjGQawwCLcB/s400/Physcomitrium%2B3%2Bfrom%2Bpond%2Bedge%2Bby%2BLSA%2B2009-02-19.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><div style="font-size: 12.8px;">
<i>Physcomitrium pyriforme</i> forms extensive colonies, and an abundance</div>
<span style="font-size: 12.8px;">of spore capsules, in the wet soil along receding ponds. </span><span style="font-size: xx-small;">(<i>Essig 20160328-1,</i> USF)</span></td></tr>
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<a href="https://1.bp.blogspot.com/-HzIqbP18mhI/Vxe52xIBqWI/AAAAAAAACrw/tWa9nurnFI8E3enjGEeTbadqicHjGQawwCLcB/s1600/Physcomitrium%2B3%2Bfrom%2Bpond%2Bedge%2Bby%2BLSA%2B2009-02-19.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><br /></a><i></i><i></i>
<i><i><span style="font-style: normal;">[Note: this species was previously posted incorrectly as </span>Physcomitrium collenchymatum<span style="font-style: normal;">]</span></i></i><br />
<i><span style="font-style: normal;">[For other mosses in this series, see the </span><a href="http://botanyprofessor.blogspot.com/p/blog-page.html" style="font-style: normal;">Table of Contents</a><span style="font-style: normal;">]</span></i><br />
<i><br /></i><i>Physcomitrium pyriforme</i> (Funariaceae) occurs along the receding edges of ponds during the dry season, and in other disturbed wet sites. It evidently completes its life cycle rapidly, producing an abundance of spore-bearing capsules in the interval before the rains fill up the ponds again.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYCe3zOpRKl4d10q1cArvvZvK-ma5pD6-4xa-Cdf33FmsY1Ill-K-Dl4yh18EQQffXrcP1_cjrB4VcbeUPs3pQMaIa_s6xQUdRrH1M0RFCurZOwHg9wKx_Q72mcY8hDKoErOs_95Fkc7uj/s1600/20160328-1+Physcomitrium+collenchymatum+%25282.5%2529.JPG" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="239" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYCe3zOpRKl4d10q1cArvvZvK-ma5pD6-4xa-Cdf33FmsY1Ill-K-Dl4yh18EQQffXrcP1_cjrB4VcbeUPs3pQMaIa_s6xQUdRrH1M0RFCurZOwHg9wKx_Q72mcY8hDKoErOs_95Fkc7uj/s320/20160328-1+Physcomitrium+collenchymatum+%25282.5%2529.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="font-size: 12.8px; text-align: center;">After losing their lids (calyptras) the capsules resemble<br />
wide-mouthed wine glasses and lack teeth around the margins. </td></tr>
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This species occurs in Florida and in other southeastern states, with outlying records in Kansas and Nova Scotia. It is distinguished from the related species, <i>P. collenchymatum</i>, by its inverted pear-shaped, rather than globose, capsules. The capsules lack any teeth around the opening, which distinguishes them from many common mosses, such as <i><a href="http://botanyprofessor.blogspot.com/2013/08/mosses-of-central-florida-4.html">Isopterygium</a></i>.<br />
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The leaves have a strong midrib and clear, rectangular to angular cells with walls irregularly thickened. The thickened appearance appears to be due to chloroplasts adhering to the walls. Leaf cells are smooth, lacking any papillae (hard, pimple-like bumps). This distinguishes this species from similar-looking members of the Pottiaceae.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7J1iuxh_nf74A5xIFwKbXwGN1WmJWr-8gzEaf_B33-3DXiSCQ21Q5egqIKRj1zEaNtXnSfxsYFO7Q6whJ15ga_QKoFfcgXk-XstznFfm0UTflQH0KS_yBtl6ip4fc0THJZhIPbO0QuQfU/s1600/20160328-1+Physcomitrium+collenchymatum+%25287%2529.JPG" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="197" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7J1iuxh_nf74A5xIFwKbXwGN1WmJWr-8gzEaf_B33-3DXiSCQ21Q5egqIKRj1zEaNtXnSfxsYFO7Q6whJ15ga_QKoFfcgXk-XstznFfm0UTflQH0KS_yBtl6ip4fc0THJZhIPbO0QuQfU/s400/20160328-1+Physcomitrium+collenchymatum+%25287%2529.JPG" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="font-size: 12.8px; text-align: center;">The leaves of <i>Physcomitrium</i> have a strong midrib, and large rectangular <span style="font-size: 12.8px;">cells.</span></td></tr>
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Note: photographs, geographic distributions and information about the naming history and synonyms of this and other mosses are currently being incorporated into the <a href="http://florida.plantatlas.usf.edu/">Atlas of Florida Plants</a>.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-k5G8rG06wWE/VxfCG4dH0QI/AAAAAAAACsU/e7D5t9D7IuA-hrqCmxHUNOmdbLdUdgwOgCLcB/s1600/20160328-1%2BPhyscomitrium%2Bcollenchymatum%2B%252811%2529.JPG" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="212" src="https://1.bp.blogspot.com/-k5G8rG06wWE/VxfCG4dH0QI/AAAAAAAACsU/e7D5t9D7IuA-hrqCmxHUNOmdbLdUdgwOgCLcB/s320/20160328-1%2BPhyscomitrium%2Bcollenchymatum%2B%252811%2529.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="font-size: 12.8px; text-align: center;">Adhering chloroplasts give the cell walls a rough, thickened<br />
appearance.<br />
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Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-20975458146221839862019-01-30T07:57:00.000-08:002019-01-30T07:57:53.487-08:00Cyanobacteria - superheroes of evolution<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-4mC-_CG48gY/XEzef3q_VoI/AAAAAAAAECk/SZvJ-diPM6o-Cf5sRoOBCn6X0axrvB0kQCLcBGAs/s1600/Cyanobacterial_Scum%2Bwiki%2BMary%2BCousins%2Bcc%2Bby%2BSA%2B3.0.JPG" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="768" data-original-width="1024" height="240" src="https://3.bp.blogspot.com/-4mC-_CG48gY/XEzef3q_VoI/AAAAAAAAECk/SZvJ-diPM6o-Cf5sRoOBCn6X0axrvB0kQCLcBGAs/s320/Cyanobacterial_Scum%2Bwiki%2BMary%2BCousins%2Bcc%2Bby%2BSA%2B3.0.JPG" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The first plants, photosynthetic cyanobacteria, are still<br />
abundant in a great variety of forms today and account for<br />
about 20-30% of the current oxygen production in the<br />
oceans. photo by Mary Cousins <a href="https://creativecommons.org/licenses/by-sa/3.0/">cc by SA 3.0</a></td></tr>
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Though it's not obvious from the name, <b>cyanobacteria </b>are photosynthetic organisms. They were actually called "blue-green algae" until it became evident that they are prokaryotes related to other bacteria. They thus have a simpler cell structure than the "true" eukaryotic algae and higher plants.<br />
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The ancestors of modern cyanobacteria invented photosynthesis over 3 billion years ago, or I should say they assembled it from processes obtained through horizontal gene transfer from at least three different ancient bacteria. (See <a href="https://botanyprofessor.blogspot.com/2012/12/the-first-plants.html">"The first plants"</a>) Earlier bacteria that harvested sunlight created carbohydrate, but the cyanobacterial process also releases releases oxygen as a byproduct, and therein lies the most important part of the story.<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-J9ICuQj7n4E/XEzghyte_RI/AAAAAAAAECw/99P72CQyrVkRkRKcmPb1v7LpQ0dqIZtEQCLcBGAs/s1600/Oscillatoria_filaments%2Bwiki%2BWiedehopf20%2B%2Bcc%2B4.0%2BInternational.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="532" data-original-width="800" height="265" src="https://1.bp.blogspot.com/-J9ICuQj7n4E/XEzghyte_RI/AAAAAAAAECw/99P72CQyrVkRkRKcmPb1v7LpQ0dqIZtEQCLcBGAs/s400/Oscillatoria_filaments%2Bwiki%2BWiedehopf20%2B%2Bcc%2B4.0%2BInternational.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Cyanobacteria, such as this filamentous <i>Oscillatoria</i> were<br />
classified as algae until their prokaryotic nature was discovered.<br />
Photo by Wiedehopf20. CC SA 4.0 International</td></tr>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQeTndo1Y3ufEGJCTUfF8cKH8_cKdyiGVphedl3XgYHRdxsSLJlo6HpsTy-raJ7hQz6lBCzSXz0dJhQh2otU4BLg134bupqFPWXAO00Z7TPqtRkXUe9sCtbE4i1rL7jIKSmeI7hVErM7_k/s1600/Chroococcus+wiki+Xvaquez+cc+sa+2.0+unported.JPG" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="130" data-original-width="138" height="187" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQeTndo1Y3ufEGJCTUfF8cKH8_cKdyiGVphedl3XgYHRdxsSLJlo6HpsTy-raJ7hQz6lBCzSXz0dJhQh2otU4BLg134bupqFPWXAO00Z7TPqtRkXUe9sCtbE4i1rL7jIKSmeI7hVErM7_k/s200/Chroococcus+wiki+Xvaquez+cc+sa+2.0+unported.JPG" width="200" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i>Chroococcus</i> is a cyanobacterium in which<br />
cells divide within a <span style="font-size: 12.8px;">gelatinous </span><span style="font-size: 12.8px;"> matrix. </span><br />
Photo by Xvazquez <a href="https://creativecommons.org/licenses/by/3.0/deed.en">CC by 3.0 unported</a>.</td></tr>
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For the first 2 billion years of their existence, cyanobacteria alone served as the base of the world's food chain, providing vast quantities of carbohydrate to feed the rest of life. That in itself was a stupendous contribution by this group of organisms, but it was the production of oxygen that changed the world forever, making more complex plants, fungi, and animals not only possible, but obligatory and inevitable. By producing oxygen as a byproduct, cyanobacteria converted the primordially anaerobic world into an aerobic one, which both enabled and forced the evolution of a variety of organisms that could note only tolerate the toxic effects of oxygen, but also put it to use through aerobic respiration. At the same time, countless and largely unknown anaerobic organisms became extinct. It may have been the first mass extinction of life on Earth. That, however, didn't happen right away - there was a 2 billion year delay - for a simple reason we'll see shortly.<br />
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All protists, animals, fungi, and higher plants are composed of eukaryotic cells. Bacteria and archaeans have the much smaller and structurally simpler cell structure we call prokaryotic. Though the name “eukaryote” emphasizes the presence of a true nucleus, these more advanced cells have additional complex organelles, internal membrane systems, and a sophisticated cytoskeleton that controls cell shape, cell and nuclear division, and the movement of organelles and materials within the cell. Such complex cells require a lot of energy for all this internal activity, and so could not have existed until oxygen was available.<br />
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When oxygen did finally become abundant in the seas, aerobic bacteria evolved, first to protect themselves, and then to harness the oxidative power of oxygen to break food materials more completely. What a boon that was! Anaerobic respiration can squeeze only 2 ATP molecules from a molecule of glucose, while aerobic respiration yields 38!<br />
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<tr><td class="tr-caption" style="font-size: 12.8px; text-align: center;">The first eukaryotic cell evolved as a flexible, amoeba-like archaean<br />
ingested aerobic bacteria, which evolved into mitochondria. Later,<br />
cyanobacteria were captured by a primitive eukaryote, and became the<br />
chloroplasts of the first true algae.</td></tr>
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Once aerobic bacteria evolved, another kind of ancient prokaryote took a shortcut to adapt to the oxygen-rich world. This one, an<br />
archaean, had already shed the rigid cell wall that surrounds most prokaryotes, and with its naked, flexible wall it could surround other cells and bring them inside for digestion. It was essentially a primitive amoeba with a rudimentary cytoskeleton.<br />
Such a cell eventually met up with an aerobic bacterium, related to modern purple non-sulfur bacteria, and took it inside. Instead of digesting the bacterium, however, a truce developed between the two cells and a deal was struck. The host cell provided food to the captured aerobic bacterium, and the bacterium in turn absorbed oxygen, used it to break down the food, and paid rent to the host cell in the form of ATP molecules. That captured aerobic bacterium evolved into the energy–processing organelle we call the mitochondrion, and that symbiotic union was the first eukaryotic cell. Incidentally, but also of huge significance, cyanobacteria were also engulfed by some early eukaryotes and became the chloroplasts we find in algae and higher plants.<br />
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This formation of the first eukaryotic cell has been considered by some scientists to have been particularly unlikely, and that only by chance did life on Earth therefore progress from the prokaryotic to the eukaryotic level of complexity. In his Scientific American article of September 2018 ("Alone in the Galaxy"), John Gribbin says “it is a measure of how unlikely such a single fusion of cells was that it took two billion years of evolution to occur.” (italics added for emphasis.) This implies that the evolutionary progress of life was stalled for two billion years and may never have gone on to form eukaryotic cells (and eventually humans), if this rare fluke of an event hadn’t happened. Gribbin and others (including the late Stephen J. Gould) believe humans exist in the universe only because of a series of such flukes. (see references below).<br />
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As I proposed in my last post (<a href="https://botanyprofessor.blogspot.com/2018/11/of-cacti-and-humans-are-certain-life.html">Of cacti and humans – are certain life forms inevitable</a>?) the evolution of life did not proceed through miraculous flukes, but rather inevitably through predictable processes. In the first place, symbiosis among prokaryotes is exceedingly common. In fact, only two months after Gribbin’s article, another article showed up in Scientific America, which suggested that symbiotic cooperation among prokaryotes might be the rule rather than the exception (see “Team Players,” by Jeffrey Marlow and Rogier Braakman, Scientific American, November, 2018). In addition, “The Runes of Evolution, by Simon Conway Morris (2015), provides abundant examples of ways in which symbiosis occurs among microorganisms, as well as providing a veritable encyclopedia of convergent evolution throughout the kingdoms of life. So it is really quite predictable that a flexible, carnivorous archaean would sooner or later run into an aerobic bacterium, ingest it, and eventually domesticate it into an internal organelle that would help it extract more energy from food items. <br />
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So what was the real reason for the 2 billion year delay? Iron. At the beginning, there was a huge amount of dissolved iron in the oceans as well as in the surface rocks. When exposed to oxygen, iron rusts, as anyone who has left tools outside too long knows. Technically speaking, this early iron was in its<b> reduced</b> state, and when exposed to oxygen it became <b>oxidized</b>. The oxidized form of iron, however, is not soluble in water, so it settled out, creating vast sedimentary deposits known as the <b>banded iron formations. </b>So all the oxygen produced by cyanobacteria was at first gobbled up by the huge amount of iron dissolved in the seas. Only after most of the dissolved iron in the oceans was depleted could oxygen start to accumulate in the environment, and that is what took 2 billion years - exactly the amount of time that some scientists propose that life was waiting for a fluke event to occur. On the contrary, it seems that the origin of eukaryotes happened as soon as it became possible.</div>
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So cyanobacteria were the first to feed the world through modern photosynthesis, they created a crisis that enabled and forced the evolution of aerobic bacteria and the first eukaryotes, and they became the chloroplasts for all eukaryotic algae and plants. Anything else? Actually, the cyanobacteria probably also invented aerobic respiration itself and passed it on to other bacteria through horizontal gene transfer.<br />
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Cyanobacteria had to have a means for protecting themselves from the oxygen they produced, and also for burning the fuel they created through photosynthesis. They most likely did this at first by running parts of the photosynthetic process backwards. Look at schematic diagrams of photosynthesis and aerobic respiration. Though details have changed over time, the two processes are roughly mirror images of each other. In modern cyanobacteria, photosynthesis and aerobic respiration take place in separate pathways, but these overlap and use some of the same protein complexes.(See <a href="https://onlinelibrary.wiley.com/doi/pdf/10.1038/npg.els.0001670">Photosynthesis and Respiration in Cyanobacteria, by W. Vermaas</a>)<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKM_wswQeCtzYWIeZRZwZbv_IoowUWTCWVYmyMEVNJAoRNC2BhIkqOKi1aPE5lHF53uq_kiV-aFDaHrKS3LS3ENXR8J-4le6jkwnb373dqPq8GvAQuXkXMddy9veNTjo4KCSa4Emabjbh8/s1600/Stromatolites+1+Paul+Harrison+Wikimedia.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="595" data-original-width="800" height="297" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhKM_wswQeCtzYWIeZRZwZbv_IoowUWTCWVYmyMEVNJAoRNC2BhIkqOKi1aPE5lHF53uq_kiV-aFDaHrKS3LS3ENXR8J-4le6jkwnb373dqPq8GvAQuXkXMddy9veNTjo4KCSa4Emabjbh8/s400/Stromatolites+1+Paul+Harrison+Wikimedia.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Stromatolites, like these in Shark Bay, Western Australia, are rare today, but<br />
were abundant in the past. They are constructed as mats of cyanobacteria <br />
and other microorganisms are laid down one on top of another. Such <br />
oxygen-rich microenvironments may have been where the first aerobic <br />
bacteria evolved. Photo by Paul Harrison, posted in <br />
Wikipedia, CC BY-SA 3.0.</td></tr>
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The evolution of aerobic bacteria might have started somewhat earlier than the appearance of oxygen in the open oceans. Many cyanobacteria lived in peculiar formations called stromatolites, some of which are still around today. These knobby pillars are formed as cyanobacteria and other microorganisms build sticky mats on their upper surface. Within these mats, oxygen may have built up locally, creating a microenvironment in which aerobic bacteria may have first evolved. There would be little fossil evidence of such soft-bodied eukaryotes, even after they moved into the open seas. Our first real evidence of eukaryotes in the fossil record was of algae who had durable cell walls. (see my earlier post on <a href="https://botanyprofessor.blogspot.com/2011/10/plants-and-animals-and-kleptoplasts-oh.html">endosymbiosis</a>.)<br />
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If all that is not enough to call cyanobacteria superheroes of evolution, there is one more thing. Whether they invented the process themselves or acquired it from some ancient bacterium through lateral gene transfer, cyanobacteria were and still are major fixers of nitrogen. This all-important process converts atmospheric nitrogen, which is inert, into ammonia, which organisms can use to make proteins, nucleotides, and countless other essential molecules. Kudos to the cyanobacteria.<br />
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BTW - Much of this is discussed in more detail in my book, <a href="https://botanyprofessor.blogspot.com/2015/02/plant-life-brief-history.html">Plant Life</a> (if you haven’t read my book yet, why not?!)<br />
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References:<br />
<br />
Gould, Stephen Jay. 1989. Wonderful Life: The Burgess Shale and the Nature of History. Norton &^ Co<br />
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Gribbin, John. 2011. Alone in the Universe - Why our planet is unique. Wiley. NY.<br />
<br />
Ward, Peter D and Donald Brownlee. 2000. Rare Earth - Why complex life is uncommon in the universe. Copernicus/ Springer-Verlag. NY.<br />
<br />
Conway Morris, Simon. 2015. The runes of evolution: how the universe became self-aware. Templeton Press. West Conshohoken, PA.<br />
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Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com2tag:blogger.com,1999:blog-8570220338076553089.post-3863840628504995472018-11-13T09:59:00.000-08:002018-11-24T12:34:27.495-08:00Of cacti and humans – are certain life forms inevitable? <div class="OutlineElement Ltr SCXW118510824" style="background-color: white; clear: both; cursor: text; direction: ltr; margin: 0px; overflow: visible; padding: 0px; position: relative;">
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">The search for alien life has been going on for almost 60 years, but so far, no one in the galaxy has returned our call. Why? There are three commonly cited reasons:</span></div>
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">1. Earth-like planets are very rare. Such planets have to be the right size, in the “Goldilocks zone” of their solar system (not too hot, not too cold, with abundant liquid water on the surface), the right distance from the chaotic center of the galaxy, have a metallic core, a relatively thin, mobile crust, and a protective magnetic field. Nevertheless, with at least 100 billion stars in our galaxy there should be a few such planets around. </span></div>
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">2. The likelihood that alien technological civilizations occurring at the same time as ours is small. Planetary systems are of different ages within our galaxy. Neither a paleolithic culture nor a long dead alien civilization, let alone a primeval world inhabited only by bacteria, is going to send or receive any radio signals. In the 3.5 billion years life has been on our planet, we ourselves have only been capable of such communication for about 100 years. Finding Paleolithic cultures (like the fictional Na'vi in Avatar) or the ruins of an ancient culture would be almost as much fun, but it's going to take more work than looking for radio signals.</span><br />
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">3. Technological humans evolved on Earth as a result of a series of lucky accidents that are unlikely to ever occur again on another planet. John Gribbin, for example, in the September 2018 issue of Scientific American, contends that “Perhaps the most unlikely of all was the development of our technological species from those first sparks of life – a feat that is probably unique.” This particular argument is one, however, that I believe is </span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">flawed and overly pessimistic. </span><br />
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<span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;"><span style="background-color: transparent;">The question of alien life is analogous to asking “are there cactus-like plants in Africa?” That may seem like a stretch, but bear with me. In any case, it’s a good excuse to talk about aliens in a blog site devoted to plants! It is also a valuable opportunity to talk about the process of evolution.</span></span><br />
<span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;"><br /></span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">It is true that <i>Homo sapiens</i> exists today as the result of a long line of very specific events. My argument, however, is that similar results can arise in alternate timelines (or other planets) involving different lineages of organisms. This is because of the power of natural selection to create, often repeatedly, distinctive life forms that play particular roles (i.e. fill particular <b>niches</b>) in the ecosystem. The often startling evidence of this power is the phenomenon of </span><b style="background-color: transparent; font-family: calibri, calibri_msfontservice, sans-serif;">convergent evolution </b><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">- the evolution of similar organisms from unrelated ancestors</span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">. In other words, life on Earth-like planets will progress in predictable ways, becoming more diverse and complex, and result in a similar mix of life forms. </span><br />
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">So, are there cactus-like plants in Africa? We have the advantage of being able to go to Africa and have a look - something we can't yet do on other planets. The cactus family evolved in the New World and did not spread into Africa until very recent times. However, two unrelated families of plants contain numerous remarkably cactus-like plants: the Asclepiadaceae (Milkweed Family) and the Euphorbiaceae (family of spurges, poinsettias and rubber trees). The remarkable similarity among these plants is a spectacular example of convergent evolution. I might be so bold as to say that, given the existence of a variety of angiosperms to start with, the evolution of cacti and cactus-like plants was <i>inevitable</i>, because of their special ability to survive in desert environments. Further, if all cactus-like plants were to become extinct for some reason, they would probably re-evolve from one plant family or another. </span><br />
<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;"><br /></span><span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">The evolution of cactus-like plants is driven by an ecological opportunity - the existence of abundant sunlight in an area where the lack of water prevents most plants from growing. Evolving from forest shrubs, the ancestors of cacti gradually honed their anatomy and physiology through natural selection, becoming adapted to survive in the deserts. The distinctive leafless, swollen, water-filled stems of cacti are what we call <b>stem succulents</b>, and we can say that they occupy a very distinctive niche in the desert environment of the New World. </span><br />
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Underutilized light, incidentally, was the ecological opportunity that drove aquatic algae to adapt to life in the terrestrial environment, becoming modern plants. Before that even, vast untapped sunlight is what drove the evolution of photosynthesis itself among ancient bacteria. Nature, via natural selection, does not let any resource go to waste indefinitely.</span><br />
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<a href="https://2.bp.blogspot.com/-gsCREeSorrk/W75eGtmtvwI/AAAAAAAAEBo/w7wwxnrAB3sATL3WDObg9YSjQfXonyc1ACLcBGAs/s1600/Succulents%2Bcombined.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="800" data-original-width="1600" height="320" src="https://2.bp.blogspot.com/-gsCREeSorrk/W75eGtmtvwI/AAAAAAAAEBo/w7wwxnrAB3sATL3WDObg9YSjQfXonyc1ACLcBGAs/s640/Succulents%2Bcombined.jpg" style="cursor: move;" width="640" /></a></div>
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Stem succulents in the Cactaceae, Euphorbiaceae, and Asclepiadaceae have remarkably similar body forms due to convergent evolution. Pictured are <i>Mammillaria dioica</i> from California (left), <i>Euphorbia stellospina</i> (center) from South Africa, and <i>Larryleachia cactiformis</i> (right), also from South Africa.</div>
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">I could give dozens of other examples of convergent evolution in plants, including carnivorous pitcher plants, hummingbird pollinated flowers, and even simple categories such as "tree," "vine," or "geophyte," each of which has evolved many times in different plant families. My argument will be that what is true for cactus and cactus-like plants on different continents could be true for humans and human-like species on different planets.</span><br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0rzdZrBVMWslsSndsQaJ02cAxbBEvPFKa_NlIAJDcI-vxfgTqrZms9awoWFg1C-JItxmZ4DARoAa1Wbst-Nzab_A8w-96CR3Pk5qOPaJlIlHdMw0cfWypzuzwRDhLQXEr4ijUOVAoNhU-/s1600/Ichtyosaurs.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="373" data-original-width="454" height="327" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0rzdZrBVMWslsSndsQaJ02cAxbBEvPFKa_NlIAJDcI-vxfgTqrZms9awoWFg1C-JItxmZ4DARoAa1Wbst-Nzab_A8w-96CR3Pk5qOPaJlIlHdMw0cfWypzuzwRDhLQXEr4ijUOVAoNhU-/s400/Ichtyosaurs.jpg" width="400" /></a></td></tr>
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<span style="font-family: "times" , "times new roman" , serif;">These remarkably dolphin-like animals are all reptiles</span></div>
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<span style="font-family: "times" , "times new roman" , serif;">that existed in the Mesozoic era. Illustration posted on</span></div>
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<span style="font-family: "times" , "times new roman" , serif;">Wikipedia, Creative Commons license.</span></div>
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Has convergent evolution occurred also in animals? Yes! Examples abound, including famously the </span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">repeated evolution of porpoise-like animals. Among the Mesozoic reptiles known as Ichthyosaurs, many porpoise-like species, whose ancestors first lived on land, were hunting fish in the sea. They themselves were repeating the body form of earlier bony fish and sharks. True porpoises and whales were later iterations from land-dwelling mammals, but of course with more advanced mammalian anatomy and physiology. Sea lions, manatees, and penguins independently adopted the same basic body form that allows for efficient movement underwater. Surely life on other planets will include one or more such fish-shaped animals.</span><br />
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Convergent evolution has resulted in numerous parallel life</div>
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forms between the marsupials of Australia and the placental</div>
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mammals of Africa and the northern continents. Image</div>
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posted online at <a href="http://biologywriter.com/backgrounder/evolution-2/evpage14/">BiologyWriter</a>.</div>
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Perhaps the most famous example of convergent evolution among mammals is between marsupials in Australia and placentals in the rest of the world. Marsupials entered Australia early on, while placentals either did not, or for some reason died out. So as placentals adapted to the varied habitats and food resources in Africa and the northern continents, marsupials adapted to similar habitats and food sources in Australia. So in Australia there are marsupial wolves, mice, cats, moles, anteaters, and grazers. There are even arboreal marsupials called cuscuses that are like primitive primates. It seems then that these distinctive life forms appear inevitably wherever there are similar habitats and food sources. In other words, when there is an ecological opportunity (an “empty niche,” if you like), organisms will adapt to exploit it. </span></div>
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">So if porpoise-like, wolf-like, mouse-like, and other animal life forms are evolve inevitably in response to particular ecological opportunities, why not humans? What does it take to make a human? </span><br />
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">To begin with, humans are mammals, rather than reptiles or birds. Live birth, maternal feeding through lactation, and the accompanying parental care seem to foster the ability to learn or pass information among individuals, an important component of human behavior and intelligence. The ancestors of primates were probably small, shrew-like mammals that had co-existed with dinosaurs for millions of years, primarily by staying out of their way, coming out at night, or by scampering up into trees. </span><br />
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<tr><td class="tr-caption" style="font-size: 12.8px; text-align: center;">Figs arose about 50 million years ago, during the early<br />
diversification of primates, and are a major source of food<br />
for birds, primates, and other animals in tropical forests<br />
around the world..<br />
Photo: <a href="https://www.loe.org/shows/segments.html?programID=17-P13-00003&segmentID=5">Bernard DUPONT, Flickr CC BY-SA 2.0</a></td></tr>
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Primates are traditionally thought to have appeared around 55 million years ago, when they began </span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">showing up in the fossil record. A radically new theory, however, places their origin at about 185 million years ago, with other estimates inbetween. Either way, their diversification in the fossil record coincides with the development of tropical rain forests increasingly dominated by angiosperms, particularly those producing tasty fruits. Tropical figs (of which there are some 850 species occurring throughout the tropics) first appear in the fossil record about 50 million years ago and have been a major food source for tree-dwelling primates, as well as birds and other arboreal animals ever since. Angiosperm trees also have broad crowns with intermingling limbs, and some angiosperms evolved also into lianas that further lace the trees together. This created a 3-dimensional, food-filled jungle gym perfect for the evolution of primates - an ecological opportunity that would almost certainly be exploited in any timeline or planet. </span><br />
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<tr><td class="tr-caption" style="text-align: center;">Primates have flexible shoulder joints allowing for <span style="background-color: transparent; font-size: 12.8px;">rotatable </span><br />
<span style="background-color: transparent; font-size: 12.8px;">limbs, as well as grasping hands and </span><span style="background-color: transparent; font-size: 12.8px;">stereoscopic, </span><br />
<span style="background-color: transparent; font-size: 12.8px;">color vision. Photo posted by Glen Tarr on Quora.com.</span></td></tr>
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Humans could not have evolved without some key anatomical innovations that arose during our ancestors' arboreal phase. Yes, our ancestors had to have been monkey-like creatures, not dogs or gazelles or dolphins or octopi, and here’s why. The hallmark feature of humanity is our ability to fashion weapons, tools, clothing, musical instruments, and ultimately space ships out of sticks, stones, and other natural materials.</span><br />
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">To do all of that we need grasping hands with opposable thumbs, eyes forward on relatively flat faces for stereoscopic vision, and something that doesn’t get as much press coverage: <b>rotatable limbs</b> - arms that can rotate around the shoulder joint and be lifted above the head. Imagine a dog or a gazelle walking up to a pitcher’s mound, winding up, and throwing a fastball across home plate. They can’t do it because of the limited flexibility of their shoulder joints. Rotatable limbs evolved in primates, along with grasping hands, as a means of swinging from branch to branch in a tropical forest, as well as for reaching edible fruits and other food items in those trees. Such limbs were essential for the earliest stages of weapon technology - throwing rocks and wielding sticks.</span><br />
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">The second crucial phase of human evolution, was, ironically, coming back out of the forest, but now equipped with grasping hands, rotatable limbs, and a higher level of intelligence, communication, and social interaction that also progressed in the trees. </span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Anthropologists still debate the ecological stimulus for the human debut, but it appears that a changing climate in Africa led to expansion of the savannas and greater variation of available food sources. The evolving intelligence of our ancestors enabled them to recognize patterns and predict where to find food in this sparse habitat, as well as to devise cooperative strategies and weapons for hunting and defending themselves. In the process, they became more upright in posture, perhaps to be able to see over the tall grass, but also to more comfortably carry and use weapons. </span><br />
<span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;"><br /></span>
<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Incidentally, when I was teaching introductory biology I did an exercise with my students critiquing fictional aliens. It is highly likely that technological, human-like aliens would have had to go through a similar evolutionary sequence as us, and therefore would look boringly like us. They too would first have to have lived in tropical trees and then have come down from those trees to have the necessary hand and shoulder anatomy for manipulating weapons. So which are evolutionarily more logical - Hutts or Vulcans? Try to imagine how each would have evolved their human-like characteristics in some other way.</span><br />
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<span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">As intelligent as octopi and dolphins might be, they could progress no further in the aquatic environment. Though octopi have some ability to manipulate objects with their tentacles, dolphins have none. Aside from that, have you ever tried to throw a rock underwater? How about lighting a fire or smelting iron for weaponry or tools? Forget also</span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;"> Lady Proxima, the giant, apparently amphibious, worm-like creature portrayed in the most recent Star Wars Film, Solo - how could such a creature evolve into an intelligent being?</span><br />
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Was the evolution of human-like creatures inevitable and repeatable? All we can say is that it was ultimately successful (perhaps too successful given our precarious environmental situation today!) and that under similar circumstances on another planet it would probably happen again. If tropical forests filled with edible fruits evolve, creatures will adapt to arboreal life. Climate change will inevitably happen, and primate-like creatures will very likely emerge from the forests and survive by their wits and their weapons. </span><br />
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<span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Was the </span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">extinction of the (non-avian) dinosaurs 65 million years ago a lucky accident necessary for the evolution of primates and humans? The question applies to mass extinction events in general, which c</span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">learly can significantly alter the course of evolutionary history (a theme of "A New History of Life," by Peter Ward and Joe Kirschvink). The survivors of such events, however, will typically re-diversify into a range of ecological niches similar to what was present before. </span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">This is what convergent evolution shows us. </span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Mammals, in fact, took over many of the niches left vacant by the dinosaurs. The actors change, but the roles they play are largely the same. </span><br />
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<span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">As an analogy, think of a village of humans wiped out by some natural disaster, except for one surviving family. That family first would have to do everything for themselves - grow food, weave cloth, make candles, etc. But as their numbers rebounded, they would begin to specialize for different economic roles, eventually specializing into the varied professions that had existed in the previous population. </span><br />
<span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;"><br /></span><span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">As for the dinosaurs, it might have been more difficult for humans to come out of the forest if <i>T. rex</i> had been still stomping around. However, when considering alternate timelines, or other Earth-like planets, the dynamics between reptiles, mammals, and angiosperm forests could work out in a variety of ways. Dinosaurs might have died out for other reasons, or if not, been no more of a threat than the large cats encountered by early humans on the savannas. See the interesting <a href="http://www.bbc.com/future/story/20170918-what-if-the-dinosaurs-hadnt-died-out">BBC post</a> on this topic.</span><br />
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<span style="background-color: transparent; font-family: "calibri" , "calibri_msfontservice" , sans-serif;">What if humans themselves had gone extinct for some reason? There is a theory that humanity barely survived an incident that took place some 70,000 years ago. Some calamity, possibly a super volcanic eruption, is said to have reduced the population of modern humans down to a few thousand. This is based on DNA evidence suggesting that all existing humans today descended from a single small population. Without getting into the debate of whether that actually happened, let’s suppose it did, and let's suppose our direct ancestors in Africa had been completely wiped out. Again, depending on what survived, we might have re-evolved via a different route. </span><br />
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">That particular event apparently didn’t affect Neanderthals, at least not to the same degree, for our rebounding ancestors met them some 20,000 years later as they moved from Africa into the Middle East. Neanderthals were already quite human, with hunting technology, clothing, and possibly religious beliefs. They might have picked up the torch if our species in Africa had been wiped out. (Maybe the Klingons were the Neanderthals of another planet!). Even if Neanderthals had been wiped out too, other surviving primates might have started the process of humanization anew. </span><br />
<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;"><br /></span><span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">There are other unlikely events cited by the alien civilization nay-sayers, including the origin of life itself, formation of the first eukaryotic cells, and other important steps. Was the evolution of multicellular animals and the progression from fishes to amphibians to reptiles and mammals inevitable? Would it likely occur the same way on another Earth-like planet? It would take a book to discuss all of these questions, though they could be analyzed in the same evolutionary framework I've used here, with examples of convergent evolution. I think the answers are generally yes.</span><br />
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<span style="font-family: "calibri" , "calibri_msfontservice" , sans-serif;">Of course, all that I have said here is speculative, but my point is that when considering the likelihood of human-like life on other Earth-like planets we must keep in mind the power of natural selection to adapt organisms to new or recurring ecological opportunities. Convergent evolution, in particular, strongly suggests that particular life forms, or “niches,” will be filled by organisms of different ancestry in different parts of the world (or galaxy), and refilled if emptied by some disaster. Humans are not the result of a series of lucky accidents, but the product of ordinary evolutionary processes. As cacti are inevitable because of their remarkable ability to survive in a particular environment, so humans might be inevitable because of their remarkable ability to survive and dominate in harsh or unpredictable environments.</span><br />
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Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com2tag:blogger.com,1999:blog-8570220338076553089.post-14569966209552983732018-07-09T13:05:00.001-07:002018-07-09T13:05:44.425-07:00The odd seed baskets of carrots<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-VlH0a5C_7t4/W0O0E7yiYEI/AAAAAAAAD_0/tf5pqwZfIfgK756Jw0hTJaIQyEJZNJDXgCLcBGAs/s1600/20180515_085632.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="900" height="640" src="https://1.bp.blogspot.com/-VlH0a5C_7t4/W0O0E7yiYEI/AAAAAAAAD_0/tf5pqwZfIfgK756Jw0hTJaIQyEJZNJDXgCLcBGAs/s640/20180515_085632.jpg" width="360" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Flowers of the carrot, <i>Daucus carota</i>, are borne in a flat-topped <br />inflorescence called a compound umbel. Ignore the <br />foliage in this photo, as it belongs to a neighboring potato plant.</td></tr>
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Most people don't notice the elegant inflorescences of the carrot plant (<i>Daucus carota</i>). If you do, it usually means you've waited too long to harvest the edible, orange taproots. If you have seen them, you might have noted the resemblance to Queen Anne's Lace, which is in fact a wild relative of the cultivated carrot. <br />
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The individual white flowers are borne in small, flat-topped clusters called umbels, for their resemblance to little umbrellas. The umbels, moreover, are grouped into a more compound structure, creating a large, flat-topped display for the tiny insects that will feed on the flowers and disperse their pollen. The carrot family, Apiaceae, used to be called the Umbelliferae, after this characteristic inflorescence structure. Celery, coriander, celantro, parsley, dill, fennel, and a host of other plants useful for nutrition and seasoning, belong also to this family.<br />
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Even fewer people have noticed the strange contortions these inflorescences undergo during their development and the maturation of their seeds. As the young flowers begin to form, they are hidden and protected within the in-turned inflorescence branches and a series of spiky bracts.<br />
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As the flowers mature, the branches of the inflorescence expand and bend outwards to form the compound, flat-topped blooming structure.<br />
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The surprise comes as the flowers wither and their ovaries mature into the tiny, one-seeded fruits, that we superficially take for bare seeds. The fruits of the carrot and other members of the Apiaceae (sunk by some into the Araliaceae) are technically schizocarps, as they consist of two single-seeded units that split apart as they mature. The fruit wall is thin, and dries into a hard outer layer on the seed, and so is unnoticed. <br />
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As this ripening process proceeds, the branches of the inflorescence bend inwards again, bringing the fruits inside of what is now a basket-like structure. It is likely that this phenomenon is an adaptation for protecting the fruits from herbivores as they ripen, but I've not been able to find any literature to verify this. The basket may also serve as a giant salt-shaker like structure that sways back and forth in the wind, helping fling the seeds away from the parent plant. A similar structure has been noticed in the related genus, <i>Conopodium</i>, and is likely to be found in other members of the family.<br />
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<tr><td class="tr-caption" style="text-align: center;">As the young flowers develop, they are protected within the in-rolled<br />branches of the inflorescence.</td></tr>
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<tr><td class="tr-caption" style="text-align: center;">As the ovaries of the flowers develop into the dry fruits known as schizocarps,<br />they are drawn inside of a basket-like structure, by the inward curving<br /> inflorescence branches.</td></tr>
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<br />Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com4tag:blogger.com,1999:blog-8570220338076553089.post-13765464219740629852018-05-20T15:15:00.000-07:002018-05-20T15:15:02.322-07:00Are palms giant herbs?<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em;"><tbody>
<tr><td style="text-align: center;"><a href="https://4.bp.blogspot.com/-oirtzla5rDc/Wm-e_z0gduI/AAAAAAAADrA/XP_V1GsZuxwlhcEl_G9qNuN_Y7mmlh7mgCLcBGAs/s1600/Corypha%2Bumbraculifera%2B2%2BZona.JPG" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="808" data-original-width="601" height="320" src="https://4.bp.blogspot.com/-oirtzla5rDc/Wm-e_z0gduI/AAAAAAAADrA/XP_V1GsZuxwlhcEl_G9qNuN_Y7mmlh7mgCLcBGAs/s320/Corypha%2Bumbraculifera%2B2%2BZona.JPG" width="238" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: x-small;">The largest inflorescence in the world </span><br />
<span style="font-size: x-small;">is that of a palm, <i>Corypha</i></span><br />
<span style="font-size: x-small;"><i>umbraculifera</i>, which like the well-</span><br />
<span style="font-size: x-small;">known Century Plants in the New</span><br />
<span style="font-size: x-small;">World, dies after its massive</span><br />
<span style="font-size: x-small;">flowering. The inflorescence</span><br />
<span style="font-size: x-small;">is said to contain approximately </span><br />
<span style="font-size: x-small;">24 million flowers. </span><br />
<span style="font-size: x-small;">Photo courtesy Scott Zona.</span><br />
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The Palm Family (Arecaceae) includes some of the largest monocots in the world, and one could argue, the largest perennial herbs.<br />
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To call a massive palm tree an herb may seem like a strange statement, since it has a sturdy upright stem, and may live for 100 years or more. Palm trunks may be a meter or more in thickness (<i>Roystonea</i> or <i>Jubaea</i>), and they hold the records for the largest inflorescences (<i>Corypha umbraculifera</i>), the largest seeds (<i>Lodoicea maldivica</i>) and the largest leaves (<i>Raphia regalis</i>) in the plant kingdom.<br />
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-YTjPR4BkIE0/Wv8xfzhwpYI/AAAAAAAAD5c/samVRpoVwI40_ovZ1eTYJEa26q5cyqbKACLcBGAs/s1600/Lodoicea%2Bseed.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="883" data-original-width="800" height="200" src="https://2.bp.blogspot.com/-YTjPR4BkIE0/Wv8xfzhwpYI/AAAAAAAAD5c/samVRpoVwI40_ovZ1eTYJEa26q5cyqbKACLcBGAs/s200/Lodoicea%2Bseed.jpg" width="179" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The largest seed in the world, weighing <br />
up to 55 pounds, is that of <i>Lodoicea maldivica</i>, <br />
from the Seychelles Islands. The large <br />
seeds are thought to be an adaptation<br />
for survival of seedlings in a thick forest<br />
with nutrient- poor soil. Posted on <br />
Wikipedia, Creative Commons license.</td></tr>
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-IOw3CK6wC_s/Wv8xpBesxyI/AAAAAAAAD5g/iNLphS5b_H4XoA7v5jk27X97-q6d0C4GwCLcBGAs/s1600/Raphia_australis.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="768" data-original-width="1024" height="474" src="https://2.bp.blogspot.com/-IOw3CK6wC_s/Wv8xpBesxyI/AAAAAAAAD5g/iNLphS5b_H4XoA7v5jk27X97-q6d0C4GwCLcBGAs/s640/Raphia_australis.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Members of the genus <i>Raphia</i> in Africa have the largest leaves of any plant. Pictured is <i>R. australis</i>, which is truly huge, <br />
but a camera-shy relative, <i>R. regalis</i>, has the largest leaves, measured at over 25 meters in length. <br />
Photo posted on Wikipedia, Creative Commons License.</td></tr>
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So is a palm a herb? The traditional definition of a <b>herbaceous plant</b> (or simply <b>herb</b>, in a botanical rather than culinary sense) is that it lacks permanent, above-ground woody stems, though they may have woody underground parts. Tulips and dahlias are examples of <b>perennial herbs</b>, while pansies and marigolds are examples of <b>annual herbs</b>. The alternate category is <b>woody perennials</b>, which include trees, shrubs and lianas. There are, in fact, some dwarf palms that do not produce upright stems. They would clearly be perennial herbs. But what about larger palms?<br />
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The vegetation of herbaceous plants is produced entirely through <b>primary growth</b>, in which all tissues arise from the apical meristems, or buds, at the tips of the stems. In contrast, woody plants exhibit <b>secondary growth</b> both above and below ground. It is important to note that wood is the production of concentric layers of <b>secondary xylem</b>.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlrOzIfwflqogKH4xTrV_Nn40nRmJ0_FiKwV3g6p52C6X2cTepVk5BuychFjcdduQeiey0z2LEG_qqAPjgIcfeUQPjreWLk8948hwSZwJOmUPhh6Jt_h4a0F8UZ7T0OBEYYZ7nLv77L9FI/s1600/Bamboo_bambou_bambuseae_phyllostachys_VAN_DEN_HENDE_ALAIN_CC-BY-SA-4_0_210520142095.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1423" data-original-width="800" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlrOzIfwflqogKH4xTrV_Nn40nRmJ0_FiKwV3g6p52C6X2cTepVk5BuychFjcdduQeiey0z2LEG_qqAPjgIcfeUQPjreWLk8948hwSZwJOmUPhh6Jt_h4a0F8UZ7T0OBEYYZ7nLv77L9FI/s640/Bamboo_bambou_bambuseae_phyllostachys_VAN_DEN_HENDE_ALAIN_CC-BY-SA-4_0_210520142095.jpg" width="353" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Are bamboos, perennial herbs or trees? Photo by Alain Van den Hende,<br />
posted on Wikipedia, Creative Commons License.</td></tr>
</tbody></table>
Tropical plants, and tropical monocots in particular, severely strain the distinction between those two categories. First of all, no monocot, even a palm "tree," has true woody tissues. Their stems, no matter how thick or dense, are produced entirely through primary growth, and are strengthened by dense masses of fibers, rather than by layers of secondary xylem. <i>For that reason alone, all monocots could be considered herbaceous.</i><br />
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Many botanists would consider that too picky, and would use the term "woody" in a broader sense to refer to the dense wood-like tissues of palms. And there are a few monocots, such as the dragon trees, giant aloes and some dracaenas, that have a specialized form of secondary growth, but such growth adds only layers of fibers and vascular bundles, not layers of secondary xylem.<br />
<br />
Even if we accept that palms and other giant monocots are trees, there are still many gray areas where one is not quite sure where herbaceous perennials end and trees begin, and so there is value in pointing out the distinction between the very different ways that monocots and dicots form tree-like growth forms (see <a href="http://botanyprofessor.blogspot.com/2012/05/invention-and-reinvention-of-trees.html">The invention and reinvention of trees</a>).<br />
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Monocots abandoned the ability to form true wood as their ancestors adapted to a growth form based on rhizomes, with leaves that elongate from the base, and short-lived upright reproductive shoots (see <a href="http://botanyprofessor.blogspot.com/2012/01/how-grass-leaf-got-its-stripes.html">How the grass leaf got its stripes</a>). Leaves of monocots, which can be relatively large, are heavily dependent on bundles of fibers for support against both gravity and wind, as well as sometimes for protection against herbivores. As they spread to a wide variety of habitats, some monocots got larger and developed upright stems with increased density of supporting fibers. Important commercial fibers come from a variety of monocots, including Manila hemp (from a type of banana), sisal (from a species of <i>Agave</i>), and New Zealand hemp (from <i>Phormium</i>). Fiber can also be teased our of bamboo stems and the leaves, stems, and fruits of many palms. <br />
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Tropical monocots tend to be evergreen, another way they differ from temperate herbs. Banana plants, which are tree-like, but clearly herbaceous, remain above ground for several years. Others, such as agaves, aloes, and birds-of-paradise have permanent tufts or rosettes of above-ground foliage, typically arising from underground rhizomes. No one would confuse such plants with woody shrubs, and these must be considered perennial herbs. Other monocots, including many grasses (e.g. canes) have upright stems that are reinforced with fibers and may last for several years. Bamboos are giant grasses with sturdy upright stems that live for many years (see <a href="http://botanyprofessor.blogspot.com/2012/03/grasses-that-would-be-trees.html">The grasses that would be trees</a>). Should they be called herbs or woody plants? Neither, actually.<br />
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<div>
The whole point of this long diatribe is to once again to point out how different monocots are from other vascular plants. Their growth forms cannot be classified in the same terms as dicots. They have mimicked the forms of many other kinds of plants (e.g. palms vs cycads), but with very different patterns of growth and tissues. Some of the elaborate classifications of the past (try googling: "plant growth forms") included special categories for palms and bamboos, but many did not. In my opinion, the term "woody" should not be used for any monocot. We can substitute the word "fibrous," which will be much more accurate and informative. Many tropical and xeric monocots can be referred to as <b>evergreen perennial herbs. </b> That would cover agaves, aloes, yuccas, and birds-of-paradise, as well as smaller palms. Tree-like monocots, such as coconut palms, bamboos, screw-pines, Joshua trees, and dragon trees, might be called <b>"</b><b>fibrous </b><b>arborescent perennials." </b> <br />
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Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com3tag:blogger.com,1999:blog-8570220338076553089.post-81490106831620079632018-03-07T04:13:00.001-08:002018-03-07T04:13:46.189-08:00Mosses of Central Florida 52. Fontinalis sullivantii<i>Fontinalis sullivantii</i> Lindberg (Fontinalaceae) is a straggling moss often found in water, but also on soil or tree bases in moist areas. Leaves are spread primarily on two sides of the stem. Note all photos are of other species, provided to illustrate the general characteristics of the genus.<br />
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<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-HsC2QmP3vVI/Wp_MbCUmmBI/AAAAAAAAD0c/I7qy2Ah5go4YpHitMKdLPAfE0uQ5RDnVwCLcBGAs/s1600/Fontinalis_antipyretica_Bernd%2BHaynold%2Bwikimedia%2Bcreative%2Bcommons.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="831" data-original-width="1024" height="323" src="https://2.bp.blogspot.com/-HsC2QmP3vVI/Wp_MbCUmmBI/AAAAAAAAD0c/I7qy2Ah5go4YpHitMKdLPAfE0uQ5RDnVwCLcBGAs/s400/Fontinalis_antipyretica_Bernd%2BHaynold%2Bwikimedia%2Bcreative%2Bcommons.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><i>Fontinalis antipyretica</i>, showing aquatic habitat.<br />
Photo by Bernd Haynold, Creative Commons license,<br />
posted on Wikimedia Commons</td></tr>
</tbody></table>
The stiff leaves lack a midrib, and the cells are worm-like, but plump, and densely filled with chloroplasts. A few cells at the base of the leaf are larger, more squarish, and clear.<br />
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Spore capsules appear along the stem and are nestled within a cluster of specialized leaves, lacking an elongate stalk.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTkPtGQRcrPNlhfCg7_WY0ijuZMaBahWjkwZyD_ZCkcFl-VQcOJ_On-fnzi82x1rK3zbgmpoeAVpovQV7R2Ux1Cl_BgvQX1OHPBUp0ofIi8ODiSUc7xYwdEIwM9DOKS2PO0q5VXRNi-VHK/s1600/Fontinalis_antipyretica1+Kurt+Stuber+Wikimedia.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="480" data-original-width="640" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTkPtGQRcrPNlhfCg7_WY0ijuZMaBahWjkwZyD_ZCkcFl-VQcOJ_On-fnzi82x1rK3zbgmpoeAVpovQV7R2Ux1Cl_BgvQX1OHPBUp0ofIi8ODiSUc7xYwdEIwM9DOKS2PO0q5VXRNi-VHK/s400/Fontinalis_antipyretica1+Kurt+Stuber+Wikimedia.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The flattened leafy shoots of <i>Fontinalis sullivantii</i>. Photo by<br />Kurt Stuber, Creative Commons license, posted on Wikimedia<br />Commons.</td></tr>
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<div class="separator" style="clear: both; text-align: center;">
<a href="https://2.bp.blogspot.com/-kYwnWdXLX9U/Wp_NGnIqREI/AAAAAAAAD0k/qTruAOzabpw79iUtwfxEB0-eWCoh9zt3QCLcBGAs/s1600/Fontinalis_antipyretica_Hermann%2BSchachner%252CWikimedia.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"></a></div>
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhoWr_wxsh3E8VTMYxQ5YIIUdWASQzaElP_eJDDb_4MoDD4VHc_Wy6ToxQnI6Dhnvaz_atZvdHPk5qOWsIPbXPy6QBubGJKS0NmztTFegN8o7fMOOGJB43uCpDFr-vz78lrWrmEFoVRvibg/s1600/Fontinalis+squamosa+leaf+Wikimedia.JPG" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="798" data-original-width="1200" height="265" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhoWr_wxsh3E8VTMYxQ5YIIUdWASQzaElP_eJDDb_4MoDD4VHc_Wy6ToxQnI6Dhnvaz_atZvdHPk5qOWsIPbXPy6QBubGJKS0NmztTFegN8o7fMOOGJB43uCpDFr-vz78lrWrmEFoVRvibg/s400/Fontinalis+squamosa+leaf+Wikimedia.JPG" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The leaf tip of <i>Fontinalis squamosa</i>, showing the curvy,<br />worm-like cells filled with chloroplasts. <br />Photo by Hermann Schachner, public domain, posted on <br />Wikimedia Commons</td></tr>
</tbody></table>
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This species occurs throughout eastern U.S. and northern Europe.<br />
It is found in northern Florida down to Hillsborough, Polk and Osceola Counties, though it has been sparsely collected.<br />
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<i>Fontinalis</i> may be confused with other aquatic mosses in Florida, but is distinguished from them by its lack of a midrib, the elongate, worm-like cells with thick walls, and the spore capsules that remain nestled within clusters of bract-like leaves.<br />
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Two other species have been collected sparsely in northern Florida: <i>Fontinalis novae-anglae</i> from the central Panhandle and possibly Orange County, and <i>F. sphagnifolia</i>, from central north Florida, with unconfirmed reports from Hillsborough and Polk Counties. They differ in small, technical details.<br />
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<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUOYt75oLlhsNWWpDzmQ2LJyRTieXnB56gZ5ITI3nJFUt3FZMwQjibqIKZ97u5JVBz7wJHGJenkj7bjKteTyhskQpS3X9GFViEKFeUpTSGeBkuwKr3oDHBKqSEvt2oeCBNjDe9kaQyLapB/s1600/Fontinalis_antipyretica_Hermann+Schachner%252CWikimedia.JPG" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="852" data-original-width="1280" height="266" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUOYt75oLlhsNWWpDzmQ2LJyRTieXnB56gZ5ITI3nJFUt3FZMwQjibqIKZ97u5JVBz7wJHGJenkj7bjKteTyhskQpS3X9GFViEKFeUpTSGeBkuwKr3oDHBKqSEvt2oeCBNjDe9kaQyLapB/s400/Fontinalis_antipyretica_Hermann+Schachner%252CWikimedia.JPG" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The base of a leaf of <i>Fontinalis antipyretica</i>, showing larger, <br />clear, basal cells, captured nicely by Hermann Schachner, public <br />domain, posted on Wikimedia Commons.</td></tr>
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<br />Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-14295961101512379372018-03-06T13:44:00.001-08:002018-03-08T03:49:43.715-08:00Mosses of Central Florida 51. Leucodon julaceus<i>Leucodon julaceus</i> (Hedwig) Sullivant (Leucodontaceae) forms colonies of erect leafy shoots arising from a branching stem system on tree trunks, logs, rock, and soil.<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/-V9jWY-FrLSA/WpKjQtmPoKI/AAAAAAAADvk/359kjF8ZvqkwivlastNg8jFyKBYAwr0dwCLcBGAs/s1600/Leucodon%2Bjulaceus%2Bhabit%2BScott%2BSchette.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1600" data-original-width="900" height="640" src="https://1.bp.blogspot.com/-V9jWY-FrLSA/WpKjQtmPoKI/AAAAAAAADvk/359kjF8ZvqkwivlastNg8jFyKBYAwr0dwCLcBGAs/s640/Leucodon%2Bjulaceus%2Bhabit%2BScott%2BSchette.jpg" width="360" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Photo by Scott Schuette, copyright MBG, posted on<br />
Tropicos, available under a Creative Commons License.</td></tr>
</tbody></table>
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Leaves are short and scale-like, with inrolled edges, evenly distributed around the stem, and lack midribs. Leaf cells are roundish-angular and largely smooth, but with some papillae on cells near the tip. When dry, the leaves press against the stem, resembling a tiny juniper twig.<br />
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Spore capsules are erect and egg-shaped, on short stalks arising from among specialized long, sword-shaped bracts, usually near the tips of the leafy shoots.<br />
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This species is found throughout the eastern U.S. and southern Ontario, as well as in Mexico and the West Indies. It is found in northern Florida south to Hillsborough and Manatee counties.<br />
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It is somewhat similar to <i>Schwetschkiopsis fabronia</i>, but the latter is confined more to the bases of trees, and the leaves are "bumpy" throughout due to the translucent cell wall projections at the ends of cells. <i>Clasmatodon parvulus</i> and <i>Papillaria nigrescens</i> are also similar but their leaves have distinct midribs.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://2.bp.blogspot.com/-8IDqE3SrE_s/WpKjzzDv71I/AAAAAAAADvs/-Sc0xfHZnyMyWrKeZnQyDcYVIdHR645ZwCLcBGAs/s1600/Leucodon%2Bjulaceus%2Bhabit%2Bclose%2B%2BGerrit%2BDavidse.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="852" data-original-width="1136" height="300" src="https://2.bp.blogspot.com/-8IDqE3SrE_s/WpKjzzDv71I/AAAAAAAADvs/-Sc0xfHZnyMyWrKeZnQyDcYVIdHR645ZwCLcBGAs/s400/Leucodon%2Bjulaceus%2Bhabit%2Bclose%2B%2BGerrit%2BDavidse.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Photo by Gerritt Davidse, copyright MBG, posted on<br />
Tropicos, available under a Creative Commons License.</td></tr>
</tbody></table>
Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-58041273351393903192018-03-01T08:55:00.001-08:002018-03-01T08:55:55.111-08:00Mosses of Central Florida 50. Cyrto-hypnum minutulum<i>Cyrto-hypnum minutulum</i> (Hedwig) W. R. Buck & H. A. Crum (Thuidiaceae)<br />
is a creeping, freely branching moss found on rotting logs, the bases of trees, and rocks.<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgKBaZbvKbecWyYjwdYnYonCMZOY36cdLNKxFfO-WODZ7MJZtvH14gNG15KuEJmwQWd8p4Yd9sE2MyecFGNTf4F4ofAG0cRP8nqbbNnOvSa_RrmNAvKOkQqTe6Ax_kYDFpF9wTMDeg5aDDa/s1600/Thuidium+minutulum+USF+108940_0024.JPG" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1065" data-original-width="1600" height="265" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgKBaZbvKbecWyYjwdYnYonCMZOY36cdLNKxFfO-WODZ7MJZtvH14gNG15KuEJmwQWd8p4Yd9sE2MyecFGNTf4F4ofAG0cRP8nqbbNnOvSa_RrmNAvKOkQqTe6Ax_kYDFpF9wTMDeg5aDDa/s400/Thuidium+minutulum+USF+108940_0024.JPG" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">A dried specimen identified as Cyrto-hypnum minutulum in<br />USF Herbarium (<i>Griepenburg s.n.</i>, 4 Apr 1970, Highland <br />Hammock State Park)</td></tr>
</tbody></table>
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The leaves are scale-like, with small roundish to squarish cells with multiple papillae on both sides. As in other members of the Thuidiaceae, leaves on the main stem are larger than on the branches. The midrib extends 2/3 to 3/4 of the leaf length. Spore capsules are asymmetrical and bent to the side.<br />
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The related genus <i>Thuidium</i> differs in that papillae are found only on the lower surface, and there is usually only one per cell.<br />
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This species is found throughout state but lacking in the southern Atlantic counties. It is also found throughout eastern N. America, Europe, and south into South America. <br />
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Also found in Florida, but very limited in distribution and distinguished on minor characteristics are:<br />
<i>C. involvens</i>, southern Florida north to Volusia County, but with major gaps.<br />
<i>C. pygmaeum</i>, 2 records: Jackson and Manatee counties<br />
<i>C. schistocalyx</i> : Highlands, Miami-Dade counties<br />
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The species has previously been known as <i>Hypnum minutulum</i> or <i>Thuidium minutulum</i>.<br />
<br />Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-69148027868723114972018-02-28T13:18:00.000-08:002018-03-06T13:26:27.638-08:00Mosses of Central Florida 49. Stereophyllum radiculosum<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4b_K8iWkSBpSDq7yXFE4uhlGFJ0su_jtxJEnqXtB9DyePbNI4YE51IFHqhkBVBMs3GiJzPZRa_VoE0DRIcSwtvBgKV8UFqEZSnzrIUbSyVTl-cjPAhim3QE1uZaxdqvtB-EchET8EYyZT/s1600/Stereophyllum+radiculosum+habit.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="603" data-original-width="800" height="301" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh4b_K8iWkSBpSDq7yXFE4uhlGFJ0su_jtxJEnqXtB9DyePbNI4YE51IFHqhkBVBMs3GiJzPZRa_VoE0DRIcSwtvBgKV8UFqEZSnzrIUbSyVTl-cjPAhim3QE1uZaxdqvtB-EchET8EYyZT/s400/Stereophyllum+radiculosum+habit.JPG" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The flat, dried leaves of <i>Stereophyllum radiculosum</i> have a<br />
conspicuously bulging midrib.<br />
Photo by Juan David Parra, copyright MBG, posted on<br />
Tropicos, available under a Creative Commons License.</td></tr>
</tbody></table>
<i>Stereophyllum radiculosum</i> (Hooker) Mitten (Stereophyllaceae) forms thin, flat mats on the base of trees, exposed roots, stumps, logs, and limestone, The distinctive flat leaves are attached uniformly around the stem (not flattened in a plane), elliptic-ovate in shape, and somewhat contorted when dry. The midrib is strong and markedly bulging, but does not reach the tip. The leaf cells are small, roundish, and contains a single papillum (translucent bump). Spore capsules are erect to somewhat leaning, asymmetrically egg-shaped, and arise from the bases of the leafy shoot on relatively short stalks (0.6-1.2 mm).<br />
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-sVFL6blWDpY/WpGiF_PdyWI/AAAAAAAADvA/i9H_1cNYHwAH-Fhz25a4ReojKXlTBlOrwCLcBGAs/s1600/Stereophyllum%2Bradiculosum%2Bcapsule.JPG" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="600" data-original-width="804" height="297" src="https://3.bp.blogspot.com/-sVFL6blWDpY/WpGiF_PdyWI/AAAAAAAADvA/i9H_1cNYHwAH-Fhz25a4ReojKXlTBlOrwCLcBGAs/s400/Stereophyllum%2Bradiculosum%2Bcapsule.JPG" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The leaning, egg-shaped spore capsule of <i>Stereophyllum</i>.<br />
Photo by Juan David Parra, copyright MBG, posted on<br />
Tropicos, available under a Creative Commons License.</td></tr>
</tbody></table>
This species is widespread in the tropics; found in the U.S. only in Alabama, Texas, and Florida, where it occurs in the southern part of the state as far north as Citrus, Volusia, and Alachua counties.<br />
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Most other creeping species found on tree bases have somewhat flattened shoots, with leaves mainly on two sides of the stem, and capsules strongly bent to the side (<i>Isopterygium</i> or <i>Haplocladium</i>) or symmetrical and upright (<i>Sematophyllum, Entodon</i>).<br />
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<br />Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0tag:blogger.com,1999:blog-8570220338076553089.post-84052115469279495162018-02-26T12:22:00.002-08:002018-03-06T13:27:34.194-08:00Mosses of Central Florida 48. Schlotheimia rugifolia<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-6dbwvcB54vs/WpRj5h3PdeI/AAAAAAAADv8/kD1VC0cmg8sZzJ9UUJ-9wIcyff_hYYzbACLcBGAs/s1600/Schlotheimia%2Brugifolia%2Bhabit.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="480" data-original-width="593" height="321" src="https://3.bp.blogspot.com/-6dbwvcB54vs/WpRj5h3PdeI/AAAAAAAADv8/kD1VC0cmg8sZzJ9UUJ-9wIcyff_hYYzbACLcBGAs/s400/Schlotheimia%2Brugifolia%2Bhabit.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The distinctive brownish shoots of <i>Schlotheimia rugifolia</i>.<br />
Photo by Juan David Parra, copyright MBG, posted on<br />
Tropicos, available under a Creative Commons License.<br />
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<i>Schlotheimia rugifolia </i>(Hooker) Schwagrichen (Orthotrichaceae) forms distinctive reddish-brown mats on logs, tree trunks, and branches. The leafy shoots are more or less erect (extending away from attached base). The flat leaves twist spirally around the stem when dry.<br />
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<tr><td style="text-align: center;"><a href="https://1.bp.blogspot.com/--3onxvcuSxg/WpHTZwnwjSI/AAAAAAAADvY/8C9ctsKl5wEfkQP9bIfmFlvuKuIFYXsLgCPcBGAYYCw/s1600/Schlotheimia%2Brugifolia%2Bcapsule.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" data-original-height="480" data-original-width="640" height="300" src="https://1.bp.blogspot.com/--3onxvcuSxg/WpHTZwnwjSI/AAAAAAAADvY/8C9ctsKl5wEfkQP9bIfmFlvuKuIFYXsLgCPcBGAYYCw/s400/Schlotheimia%2Brugifolia%2Bcapsule.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">The narrow-ovoid capsules are usually erect, but bent in this<br />
dry specimen. Photo by Juan David Parra copyright MBG,<br />
posted on Tropicos, available under a Creative Commons<br />
License.<br />
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The leaves of this species are elliptic, with short point at tip and have a slight rumpled (rugose) appearance. The midrib is strong, extending through to the short point. Leaf cells are small, roundish, and smooth. The spore capsules are erect and narrow-ovate in shape. They arise from the tips of the leafy shoots on elongate stalks,<br />
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<i>Schlotheimia rugifolia</i> is found throughout the southeastern U.S. as far north as Virginia and Tennessee, and extensively in the New World tropics. In Florida, it has been collected throughout the state but with gaps. In particular, it has not been collected in any of the Atlantic coastal counties between Volusia and Miami-Dade.<br />
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This is one of the relatively few mosses found in Florida that occur relatively high on the trunks and branches of trees. The dark, reddish brown coloring, the distinctive spiral twisting of the dried leaves and the longer capsule stalks will distinguish it from others, such as <i><a href="http://botanyprofessor.blogspot.com/2015/01/mosses-of-central-florida-8.html">Sematophyllum</a></i>, <i><a href="http://botanyprofessor.blogspot.com/2015/02/mosses-of-central-florida-10-cryphaea.html">Cryphaea</a></i>, and <i><a href="http://botanyprofessor.blogspot.com/2015/04/mosses-of-central-florida-12.html">Forsstroemia</a></i>, in this habitat.<br />
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.Frederick B. Essighttp://www.blogger.com/profile/00990515994555983108noreply@blogger.com0