Monographs Details: Hypopterygium
Authority: Sharp, Aaron J., et al. 1994. The Moss Flora of Mexico. Part Two: Orthotrichales to Polytrichales. Mem. New York Bot. Gard. 69 (2)
Description:Genus Description - Plants slender to robust, green or blue-green, gregarious to tufted. Primary stems creeping, elongate, radiculose; secondary stems ± elongate, erect or ascending, the stipitate base short or elongate with remote leaves, sometimes radiculose at the base or throughout, the frond oblique or horizontal, flattened, rounded, broadly ovate, or triangular, its branches often 1-2-pinnate, rarely 3-pinnate. Lateral leaves complanate-spreading, ± decurved or, rarely, shriveled or contorted when dry, asymmetric, ovate, oblong-ovate, or oblong-lingulate, acute or apiculate to subulate, mostly bordered by linear cells and ± serrate above; costa single, ending well below the apex; cells rhombic or oblong-hexagonal, not or slightly thick-walled, smooth; lower cells longer and laxer. Ventral leaves small, ± appressed, symmetric, broadly ovate or rounded, acute to subulate, mostly bordered, entire or serrate above. Perichaetial leaves slenderly long-acuminate from an oblong or broad, sheathing base, entire. Sporophytes often clustered; setae mostly elongate, somewhat flexuose, smooth; capsules exserted, inclined to horizontal or, rarely, pendent, mostly large, oblong-ovoid to oblong-cylindric, with a thick, ± pustulose neck; annulus ± developed, sometimes persistent; operculum long-rostrate from a convex-conic base; exostome teeth lanceolate, subulate, cross-striolate below, papillose above, with a median zigzag line, bordered, trabeculate at back; endostome papillose, the basal membrane high, segments lanceolate, keeled and usually perforate, and cilia short or well-developed. Spores spherical. Calyptrae conic-mitrate or cucullate, naked.