Monographs Details: Rhachithecium
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:Orthotrichaceae
Scientific Name:Rhachithecium
Description:Genus Description - Leaves folded lengthwise and erect-incurved or slightly crisped when dry, erect-spreading when moist, oblong-broadly acute to rounded-obtuse, sometimes shortly cuspidate; margins plane, ± crenulate toward the apex; costa slender, vanishing well below the apex; upper cells rounded-hexagonal, smooth, mammillose, or unipapillose, thin-walled, green; basal cells oblong, 2-4: 1, smooth, hyaline, thin-walled, somewhat narrower toward the margins. Perichaetial leaves 3, conspicuously convolute-sheathing, pale-yellow, oblong-lanceolate, broadly acute or obtuse; costa ending well below the apex; cells thin-walled and hyaline, those at the apex rhombic, the others long-rectangular to linear. Setae erect and usually strongly twisted above when dry, erect, flexuose, or strongly curved when moist, 0.9-1.2 mm long, yellow; capsules slightly exserted, strongly 8-ribbed and strongly contracted below a wide mouth when dry, ellipsoid and scarcely ribbed when moist; annulus narrow and persistent or broader and deciduous; operculum conic, obliquely apiculate to short-rostrate; peristome teeth none or inserted below the mouth and fused in 8 pairs, smooth. Spores spherical to ellipsoidal. Calyptrae cucullate, moderately to strongly papillose because of projecting upper ends of cells.