Monographs Details: Crassicosta
Authority: Sharp, Aaron J., et al. 1994. The Moss Flora of Mexico. Part Two: Orthotrichales to Polytrichales. Mem. New York Bot. Gard. 69 (2)
Family:Amblystegiaceae
Scientific Name:Crassicosta
Description:Genus Description - Small plants in loose, flat, slightly shiny, red or red-yellow mats. Stems creeping, irregularly branched; rhizoids in tufts on the lower surface; pseudoparaphyllia foliose, variously toothed and divided; paraphyllia few, scattered, ± linear. Stem and branch leaves similar, soft, subsecund, 0.8-1 mm long, lanceolate or ovate-lanceolate, slenderly long-acuminate; margins subentire to serrulate from the base to the excurrency ofthe costa; costa red, single, relatively stout, filling the acumen or nearly so and excurrent; upper and median cells elongate-rhomboidal, 4-5:1, papillose at back because of projecting upper ends; inner basal cells broader, papillose; alar cells small, subquadrate, not inflated, smooth. Sporophytes unknown.

Discussion:

The genus of a single species is characterized by reddish, subsecund leaves, stout, excurrent costae, rather short, papillose upper and median cells, small alar cells, and both paraphyllia and pseudoparaphyllia on the stems.