Monographs Details: Lepyrodon
Authority: Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.
Description:Genus Description - Plants medium-sized, or less often small, in mostly densely tufted mats. Primary stems creeping, filiform, inconspicuous, with reduced leaves, turning ca. 90° and becoming the secondary stem, the creeping stem continuing by a bud from near the base of the secondary stem, secondary stems erect, simple or rarely few-branched; in cross-section with small thick-walled cells surrounding larger thinner-walled cells, central strand differentiated; paraphyllia none; pseudoparaphyllia filamentous or absent; axillary hairs with 1-2 short-rectangular brown or rarely hyaline basal cells and 1-2 elongate hyaline distal cells. Secondary stem leaves erect to erect-spreading, lanceolate and plicate or ovate and smoothly concave, often piliferous, sometimes abruptly so; margins mostly toothed above or throughout, plane or irregularly incurved; costa single and weak, rarely short and double; cells mostly linear and subflexuose, sometimes long-hexagonal, smooth, often thick-walled and porose; alar cells few in extreme basal angles, firm-walled, not porose, often hyaline. Asexual propagula often by flagellate branches. Dioicous, with male plants sometimes dwarf and intertwined with female plants and attached by rhizoids. Perichaetia lateral, large and conspicuous but sometimes obscured by tomentum; leaves lanceolate to oblong, cuspidate to piliferous, not plicate; margins usually strongly toothed at base of acumen, plane; costa mostly weak; cells usually strongly thick-walled and porose. Setae elongate, smooth; capsules erect and symmetric; exothecial cells subquadrate, firm-walled, stomata immersed or superficial; annulus differentiated; operculum obliquely rostrate from a conic base; peristome seemingly single, endostomial, pale, irregular, with the basal membrane very low to conspicuous, segments flat, mostly irregularly perforate, cilia absent or rudimentary. Spores spherical, papillose. Calyptrae large, cucullate, naked to sparsely erect-hairy, smooth.
Discussion:Discussion. Lepyrodon is a genus of about six species, best represented in southern Argentina and Chile, with outliers up the Andes to Mexico (disjunct to Hispaniola) and in Australia and New Zealand. Presumably because of the weakly costate, plicate leaves in some of the species, it traditionally (Brotherus, 1925) has been aligned with Leucodon. However, it seems more closely related to the Pterobryaceae, as discussed above. The genus seems to have two groups of species, based on a preliminary, superficial examination. One group (based on the type of the genus, L. suborthostichus = L. tomentosus) has lanceolate, plicate leaves, dwarf males, and immersed stomata. The other group (e.g., L. lagurus (Hook.) Mitt.) has ovate, concave leaves with perigonia-bearing plants similar to those with perichaetia, and superficial stomata. These two groups may deserve taxonomic recognition, perhaps even at the generic level. However, since the only West Indian species is a true Lepyrodon I have not pursued the problem further.