Leaves (aerial stems) usually tightly appressed; base conspicuously pubescent. Strobili sometimes with apical vegetative growth, distinctly larger in diameter than subtending stem. Sporophylls abruptly tapering toward apex; apex often recurved.

Mostly on dry, exposed sand dunes, white sand, or sandy soil; 0 m; Fla., Ga.

Selaginella arenicola subsp. arenicola usually has more slender (1 mm diam.) stems than subsp. riddelli (stems more than 1 mm diam.). In Georgia, many forms intermediate between the two subspecies have been reported.