Hymenophyllum marginatum Hook. & Grev.

Lamina simple, once or rarely thrice forked. Involucre and/or the lamina with a black thickened margin Tiny mat-forming ferns. Rhizome wiry, sparsely clothed with a few undivided hairs. Stipes 0.3–7 mm long, filiform. Lamina simple, once or more rarely twice forked, thin, light green, linear to narrowly oblong, 4–35 mm long, 1–2.5 mm broad, glabrous; margins entire, glabrous, composed of 1–2 rows of black cells. Midrib black, glossy, without any lateral branchlets, clothed with a few, reddish, tubular hairs. Sori solitary at the apex of the frond or its lobes. Involucre oval or orbicular, 2-valved to the base, 0.8–1.5 mm long, light green, with a glossy black border 2–3 cells in width. Spores tetrahedral-globose or globose. Widespread but uncommon. RF, often near waterfalls, on rocks, logs or wet cliff-faces