1. Selaginella P. Beauv. (spikemoss)
Plants perennial, heterosporous. Stems mostly prostrate (erect or pendant
elsewhere), the branch tips somewhat ascending in some species, forming loose
to dense mats. Leaves scalelike, with a small, scaly appendage near the base of
the upper surface. Sporangia mostly ovoid occurring singly on the upper side of
the bases of leaves, these 4-ranked in dense strobili at the branch tips.
Megasporangia with (1, 2) 4 trilete megaspores, each 0.2–1.0 mm in diameter,
variously ornamented. Microsporangia with several hundred trilete microspores,
each 18–60 mm in diameter,
papillose to spiny. Gametophytes endosporic within the megaspore walls. About
700 species, worldwide.