2. Lycopodium L. (clubmoss)
Stems branching, often differentiated into a horizontal rhizome and an erect,
aerial branching system. Leaves usually dimorphic or trimorphic, the leaves of
the horizontal axes different from those of the aerial stems, and these different
from the sporophylls. Gemmae not produced. Sporangia in strobili at the tips of
aerial branches. Gametophytes subterranean, mycorrhizal, lacking chlorophyll,
obconic or irregularly disk-shaped. About 40 species, nearly worldwide, but
mostly in temperate to Arctic regions, or at high elevations in the tropics.