紫萼藓科   zi-e xian ke

by Cao Tong, Si He, and Dale H. Vitt

 

Plants small to rather robust, yellowish green to dark-green, brown or blackish below, in dense cushions or dense to loose tufts. Stems erect or prostrate, forked or moderately branched from innovations, sometimes fasciculately branched or shortly tuft-like laterally branched, rhizoids often present at the base; with or without central strand in transverse section. Leaves in many rows, imbricate, erect or somewhat contorted to occasionally crisped when dry, erect-spreading to wide-spreading when moist, mostly lanceolate to sometimes narrowly lanceolate, rarely oblong-ovate or ovate, keeled or concave, acute at apex, often muticous or ending in a hyaline hair-point; margins recurved, plane or slightly incurved, often bistratose above; costa strong, single, percurrent, subpercurrent or ending below the leaf apex; upper cells small, rounded-quadrate to irregularly short-rectangular, usually obscure, unistratose or usually bistratose to 3–4-stratose toward the apex, smooth, sometimes papillose, thick-walled, the cell walls sometimes sinuose or nodulose; lower cells near margins subquadrate, quadrate to rectangular, thinner-walled or with transverse walls thicker than the longitudinal ones, juxtacostal cells elongate, with walls straight or often somewhat to strongly sinuose or nodulose. Autoicous or dioicous. Perichaetial leaves similar to vegetative leaves, but larger, loosely areolate or differentiated with membranous and pallid margins. Setae terminal or lateral, straight or arcuate, short or elongate, sometimes shorter than the urn; capsules erect or horizontal to pendent, immersed to long-exserted, obovoid, subglobose to oblong-ovoid or cylindrical, smooth to ribbed; exothecial cells mostly elongate-hexagonal, thin-walled; stomata sometimes present at base of urns; annuli usually present, sometimes absent, consisting of quadrate to shortly rectangular cells with thick walls; opercula conic or convex, with short or long, erect to somewhat oblique beak or without a beak; columella sometimes persistent, not falling with opercula; peristome single, with 16 red-brown to yellowish brown teeth, erect, lanceolate to linear-lanceolate, entire or imperfectly perforate and split above, papillose on both the outer and inner surface, the peristome teeth sometimes reduced or absent. Calyptrae small, covering upper portion of urns, sometimes large, covering most of the urns (campanulate), usually mitrate or cucullate, smooth or sometimes plicate. Spores small, 7–16 µm in diameter, green to yellowish green, smooth to more or less granulose or papillose.