Wednesday, November 8, 2017

Mosses of Central Florida 37. The genus Thelia

The leafy shoots of Thelia resemble the the scaly shoots of
junipers.  All photos are of T. asprella, and taken by
Robert A. Klips, Ohio Moss and Lichen Association.
The three species of Thelia (Theliaceae) found in Florida have distinctive juniper-like leafy shoots, with short, scale-like leaves that are pressed to the stem even when wet. They include  Thelia asprella (Schimper) Sullivant, T. hirtella  (Hedwig) Sullivant, and T. lescurii Sullivant.  The first two species occur primarily as spreading mats at the bases or trunks of trees, on rotting logs, or soil, but T. lescurii occurs only on soil or thin soil over rocks.
The spore capsules of Thelia are upright, cylindrical and
symmetrical.
The short, stiff leaves typically have only rudimentary, usually forked, midribs at their bases, and the margins are raggedly toothed. Leaf cells are roundish or somewhat elongate, with distinct, columnar papillae. Spore capsules are upright, cylindrical, and symmetrical or slightly curved, atop  stalks that are usually little more than a centimeter high.
The short, broad leaves of Thelia species have ragged edges and elongate papillae.

All three species are found throughout the eastern U.S., including the northern 2/3rds of Florida, though T. lescurii is less common.

Thelia hirtella is distinguished primarily by its simple papillae, as opposed to the branched, compound papillae of the other two species.  In T. lescurii, the leafy shoots are only sparsely branched and tend to be more upright, as opposed to T. asprella, in which the stems spread more horizontally and are densely branched.

The species of Thelia might be confused with Entodon seductrix, which has similar, scale-like leaves, but the leaves of the latter are smooth-margined or with a few small teeth at the tip, and the cells are long, worm-like, and without papillae.

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