Monographs Details: Fissidens michoacanus Thér.
Synonyms:Fissidens brouardi Thér.
Description:Species Description - Plants dull green. Stems monomorphic, unbranched, to 4.5 mm long x 2 mm wide; rhizoids basal, smooth, reddish; axillary hyaline nodules absent; epidermis and outer tier of cortical cells small, incrassate, pigmented; inner cortical cells larger, thin-walled, hyaline; central strand present or absent. Leaves crispate, somewhat inrolled from tips when dry, loosely imbricate, as many as 12 pairs, ovate to lingulate, obtuse to rounded, sometimes ending in a sharp, clear apical cell, to 1.5 mm long x 0.3 mm wide; margin ± crenulate, limbate on proximal 1/2-2/3 of vaginant laminae of perichaetial and other well-developed leaves of perichaetial stems, proximal part often intralaminal, limbidial cells unistratose; costa ending 12-20 cells below apex, distally often spurred, bryoides type; dorsal lamina narrowed, ending above insertion to rounded and ending at insertion; vaginant laminae of cauline leaves 2/3-3/4 leaf length, acute, ± unequal, minor lamina ending a short distance from margin; laminal cells obscure, eguttulate, unistratose, firm-walled, pluripapillose, rounded-hexagonal, 4-5 µm long, in transverse section twice as deep as wide. Monoicous (rhizautoicous); perigonial branches short, at base of perichaetial stems. Sporophytes 1 per perichaetium, reddish-brown; seta smooth, to 2.5 mm long; theca exserted, cylindric, erect, radially symmetric, stomatose, exothecial cells quadrate to oblong, vertical walls thicker than horizontal walls to 0.9 mm long; peristome anomalous, deeply inserted, deeply divided, fragile, erect both wet and dry, papillose proximally, filaments spirally thickened; operculum not seen. Spores finely papillose, 7-11 µm diam. Calyptra not seen.
Discussion:Fissidens michoacanus is characterized by its pluripapillose laminal cells, limbidium restricted to perichaetial and subtending larger leaves, cylindric theca, and deeply set, anomalous peristome. The gametophyte is markedly similar to that of F. pallidinervis, and without the sporophyte it is doubtful the two species can be distinguished. However, F. pallidinervis differs by its ovoid capsule, and typical scariosus type peristome.
Michoacán Mexico North America
| Nayarit Mexico North America
| Sinaloa Mexico North America