Club Mosses

Plants terrestrial or epiphytic, perennial, usually herbaceous. Main stem cylindrical or polyhedral, short or elongated, not tuberous except in the genus Phylloglossum. Leaves simple, usually small, in spirals or whorls, arranged along simple or more usually branched stems or borne in a tuft at the base of a short, erect, unbranched stem. Sporophylls similar to the sterile leaves and arranged in fertile zones along the stem and branches or modified and clustered in strobili. Sporangia unilocular, reniform, bivalvate, occurring singly in the axils of the sporophylls. Spores uniform, globoso-tetrahedral. 4 gen., cosmop.