LYCOPODIACEAE (Clubmoss Family)

Plants perennial, homosporous. Stems sometimes rhizomatous, sometimes flattened on portions of the plants. Leaves evergreen, needlelike or scalelike, lacking a small scaly appendage (ligule) near the base of the upper surface. Specialized green, leafy structures known as gemmae (for asexual reproduction) sometimes produced on short, modified branches. Sporangia kidney-shaped, occurring singly on the upper side of the leaf bases, aggregated into strobili at the tips of aerial stem branches or located in the axils of relatively unmodified leaves along the stems, containing numerous spores. Spores 20–60 mm in diameter, trilete, light yellow, smooth to variously pitted or grooved. Gametophytes variously shaped, but not largely enclosed by the spore wall at maturity. Four genera, 350–400 species, worldwide.

The generic classification within the Lycopodiaceae remains controversial, with some authors recognizing only two genera and others recognizing as many as 10–15 segregates. The present treatment follows the classification of Øllgaard (1987, 1990), who recognized four genera. The other two genera, Lycopodiella and Phylloglossum, occur elsewhere.