Plants terrestrial or on rock, forming clumps. Stems radially symmetric, underground (rhizomatous) and aerial, not readily fragmenting, irregularly forked; rhizomatous and aerial stems often with 1 branch arrested, budlike, tips straight; rhizomatous stems mostly ascending; aerial stems erect or ascending. Rhizophores borne on upperside of stems, restricted to rhizomatous stems, 0.2--0.33 mm diam. Leaves dimorphic, in pseudowhorls of 4. Rhizomatous stem leaves persistent, appressed, scalelike. Aerial stem leaves tightly or somewhat loosely appressed, ascending, green, narrowly triangular-lanceolate or narrowly lanceolate, 2--3 X 0.4--0.5 mm; abaxial ridges present; base cuneate, strongly decurrent, pubescent or glabrescent; hairs restricted to base; margins short-ciliate, cilia transparent, scattered, spreading at base, dentiform and ascending toward apex, 0.02--0.07 mm; apex plane, attenuate; bristle white to whitish, straight, coarsely puberulent, 0.25--0.85(--0.9) mm. Strobili solitary, (0.5--)1--3(--3.5) cm; sporophylls ovate-lanceolate to lanceolate, often abruptly tapering toward apex, abaxial ridges not prominent, base glabrous, rarely with few hairs, margins ciliate, apex often recurved, bristled.