Plants polytrichoid, medium-sized to robust, in loose tufts. Stems simple to sparingly (or fasciculately) branched, arising from a short underground rhizome. Leaves with ± differentiated sheathing base and divergent blade; sheath entire, hyaline-margined, often nitid, ± abruptly contracted to the blade, the shoulders with well-developed hinge tissue; marginal lamina sharply toothed to entire; costa typically short-excurrent or (in perichaetial leaves) prolonged into a toothed awn, rarely the apex cucullate; lamellae numerous, closely spaced, occupying most of the distal surface of the blade, the margins ± entire, finely serrulate or crenulate in profile, smooth or coarsely papillose, the marginal cells in section undifferentiated or sharply distinct. Sexual condition dioicous or polygamous. Seta solitary. Capsule terete or more commonly 4-6-angled, the hypophysis tapering or distinct and cylindric but not sharply delimited; exothecium smooth, the cells not bulging or papillose, not pitted, sometimes with a diffuse thin spot on the outer wall; stomata numerous; operculum rostrate with a distinct beak; peristome not deeply pigmented, the teeth regularly 64, or somewhat fewer and irregular with some teeth compound, not keeled at back; epiphragm with erect tooth-like processes opposite the peristome teeth and loosely attached to their inner face. Calyptra cucullate, hidden by an interwoven mat of hairs covering the distal portion of capsule. Spores finely papillose.
|[Genus Polytrichum and Latin -astrum, incomplete resemblance]|