Herpetineuron toccoae (Sull. & Lesq.) Cardot

Plants rather robust, in open, dull, dark greenish to yellowish brown mats. Stems prostrate, sparsely branching; branches (1-)2-4 cm long, (0.2-)0.9-1.3 mm thick when dry, rather arcuate, terete when dry, branching pattern often consisting of several orders of successive branching in a stepwise fashion, circinate or, often, attenuate toward the apex, with a well-differentiated central strand of smaller cells, without paraphyllia or pseudoparaphyllia. Branch leaves incurved, secund, involute in a tubular fashion when dry, erect, not complanate when moist, ovate-lanceolate, tapering from the base, without an obvious constriction, 1.8-2.8 mm long, 0.5-1.2 mm wide; margins flat, irregularly and strongly serrate in the distal 1/3-1/4, serrations consisting of 1 to several cells; apex sharply acuminate; costa single, strong, pellucid, almost always sinuose in the distal 1/3, smooth on the back, not obscured by laminal cells, ending sharply at or near the apex, not bifid at the tip; laminal cells ± homogeneous throughout the lamina, rectangular to rhombic, slightly longer than wide, smooth, walls somewhat thickened. Perichaetia found on youngest branches; perichaelial leaves 1.5-2.2 mm, flexuose-subulate, often somewhat crispate, laminal cells smooth throughout. Seta 14-16 mm, light reddish brown. Capsule erect, almost symmetrical, yellow to reddish brown; urn (1.7-)2.0-2.8 mm, stomata few, cells at mouth and annulus well differentiated; operculum conic; peristome fairly well developed, exostome ca. 0.5 mm high, papillose and faintly striolate at the base and above, endostome papillose with a basal membrane to 3-4 cells high (0.05-0.15 mm), segments 0.2-0.3 mm high, papillose throughout. Spores 16-22 µm in diameter, densely papillose.