Wednesday, March 27, 2019

Mosses of Central Florida 52. Gemmabryum apiculatum

Gemmabrum apiculatum forms thick cushions, with well-spaced leaves on
the shoots.
Gemmabryum apiculatum (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.

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 ┬Ám long. I have not yet seen spore capsules in our area.


Brown, pear-shaped bulbils in the leaf axils are characteristic of
Gemmabryum apiculatum. Photo by Ainun Nadhifah
Gemmabryum apiculatum 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. 
G. coronatum 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.
A third species, G. exile, has been reported only from Collier County, but is easily recognized by its stringy stems and small, folded leaves.


The leaf of Gemmabryum apiculatum features a strong
 midrib, and elongate cells that become squarish toward the base,
Photo by Ainun Nadhifah





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Wednesday, March 6, 2019

Mosses of Central Florida 15. Physcomitrium pyriforme

Physcomitrium pyriforme forms extensive colonies, and an abundance
of spore capsules, in the wet soil along receding ponds. (Essig 20160328-1, USF)

[Note: this species was previously posted incorrectly as Physcomitrium collenchymatum]
[For other mosses in this series, see the Table of Contents]

Physcomitrium pyriforme (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.
After losing their lids (calyptras) the capsules resemble
 wide-mouthed wine glasses and lack teeth around the margins.  

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, P. collenchymatum, 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 Isopterygium.

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.
The leaves of Physcomitrium have a strong midrib, and large rectangular cells.
Note: photographs, geographic distributions and information about the naming history and synonyms of this and other mosses are currently being incorporated into the Atlas of Florida Plants.

Adhering chloroplasts give the cell walls a rough, thickened
appearance.