Thursday, December 5, 2013

Mosses of Central Florida 5. Syrrhopodon incompletus

Syrrhopodon incompletus growing on the spongy trunk
of a date palm (Phoenix dactylifera) on the University
of South Florida campus
[For other mosses in this series, see the Table of Contents]

Syrrhopodon incompletus Schwaegr. (Calymperaceae) is a relatively common moss found throughout the coastal plain of the southeastern U.S., occurring mostly on tree trunks, including palms, and exposed roots. It has a short upright stem with relatively large leaves, typically 3-5 mm in length, crowded into a circular pattern called a rosette ("rose-like"), and thus superficially resembles Octoblepharum.  The leaves are thinner, however, just one cell thick except for the prominent midrib, with small teeth along the margins, and are translucent green.
The leaf cells of this species are small, roundish and thin-
walled, and each has a small, hard, pimple-like outgrowth
called a papilla.  The marginal cells are similar in size, shape,
and coloration, but with an occasional short tooth.
The leaf cells are roundish or polygonal and thin-walled.  This genus is also characterized by an extensive and conspicuous basal region of large rectangular clear cells.  Leaf cells and the midrib have tiny rounded outgrowths called papilli, particularly on the back side.  When dry, the leaf margins roll inward, creating an almost tubular configuration, and this then twists and curls irregularly.

The large leaves have a strong midrib (or costa) and the basal region is composed of large, empty, rectangular cells.
When dry, the leave roll into a tube and then twist and curl.
The capsules (sporangia) arise from the tips of the stems, and are upright, symmetrical, and narrowly ovoid to cylindrical (when dry).  Teeth of the capsule mouth (peristome) are short and attached below the rim.  
The sporophytes arise from the tips of the stems, and the sporangia are upright and symmetrical.
Several other species of Syrrhopodon occur in Florida.  S. incompletus is characterized by the marginal cells of its leaf, which are slightly thickened but green and shaped more-or-less like the other cells of the leaf.  The other species have distinctive elongate, clear cells along the margin. S. texanus also has much more prominent spines along the margins and particularly on the lower midrib.