Genus PhyscomitriumGenus PHYSCOMITRIUM, Brid.
The species of the Genus Physcomitrium rarely live more than one year. They have a delicate texture and grow in loose tufts. The plants are sparingly branched, and bear comparatively large, soft, obovate or spatula-shaped, taper-pointed leaves with large transparent cells.
The spore-cases are ovate or spherical, and erect upon immersed or exserted pedicels. They have convex lids but no teeth, and the spore-sac (sporangium) is free from the spore-case wall, adhering to it only by thread-like strands. The veils are lobed at the base and scarcely descend to the middle of the spore-case.
The generic name Physcomitrium is a combination of two Greek words for; a fat paunch, and; a conical cap. The two words together describe the veil (calypira) as a conical cap with an inflated base.