in botany, a genus of the cryptogamia musci clas. The anthera is double-valved, and fleshy; the calyptra is wanting. There are 24 species, of which six are natives of Britain, viz. the clavatum, or common club-moss; the inundatum, or marsh club-moss; the annotinum, or Welsh club-moss; the alpinum, or mountain club-moss; the felago, or fir club-mosses; and the selaginoides, or prickly club-mosses.