Monographs Details: Haplohymenium
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 - Small plants in dull, dark- or yellow-green to brown, rigid mats. Stems freely and irregularly branched; branches when dry, spreading or ascending; paraphyllia none. Stem and branch leaves similar, crowded, imbricate when dry, spreading to squarrose when moist, not phcate, sometimes fragile, ovate at base and gradually or abruptly narrowed to a lingulate to lanceolate point, rounded-obtuse to acute, sometimes minutely apiculate; margins plane, crenulate all around because of bulging cells (rarely serrulate at the tips); costa single, slender and ending at or below the leaf middle or, rarely, stronger and ending below the apex, smooth; cells green, hexagonal, thin-walled, bulging and pluripapillose on both surfaces (or, rarely, stoutly unipapillose), oblong, incrassate, and pellucid at the middle ofthe insertion. Dioicous. Perichaetial leaves larger, erect, oblong-ovate, gradually acuminate. Setae relatively short (1.5-5 mm long); capsules erect and symmetric, broadly ellipsoid, brownish; annulus narrow but well developed, fragmenting; operculum rostrate from a convex-conic base; exostome teeth short, narrowly lanceolate, perforate along the median line, pale-yellowish, rather coarsely papillose; endostome a smooth, very low, and inconspicuous membrane. Calyptrae cucullate, ± lobed at the base, rough at the apex, bearing few to several erect hairs.
Haplohymenium is segregated from Anomodon on the basis of more slender gametophytes, oblong-ovoid capsules, exostome teeth with large papillae or irregular thickenings, endostome without segments or ciha, and hairy calyptrae.