Greekpsilos, naked, smooth, alluding to the smooth aerial stems.
Plants slender, medium-sized, terrestrial or epiphytic. Subterranean stems rootless, occasionally bearing minute gemmae, rhizoids present anchoring plants at bases. Stems above-ground upright or pendulous, dichotomously forked, or undivided, often clumped, 2-3 ridged, green. Leaves minute, remote, awl-shaped, 0.5-2 mm long, lacking veins, or leaves larger, subsessile, narrowly ovate to lanceolate, obtuse to acute with bifid fertile leaves. Sporangia in groups of 2 to 3, fused into a single, lobed, globular synangia, about 2 mm in diam., borne distally on ridges of branchlets, or in axils of bifid leaves.
A primitive family of two genera in tropical and warm-temperate regions. Represented in Hawai 'i by the genus Psilotum.
