Hymenophyllaceae
Fronds delicate, translucent, usually 1 cell thick, lacking stomates. Receptacle elongated and columnar. Epiphytic or rupestral ferns under 12 cm high Hymenophyllaceae
Involucre bivalvate (deeply or to the base) or bivalvate in the upper portion but obconic at the base Hymenophyllum
Margin of the lamina and the axes not clothed with branched hairs
Margin of the lamina denticulate
Involucre bivalvate in the upper portion but obconic at the base Rhizome long-creeping, wiry, 0.3–0.8 mm diam., clothed sparsely especially at the nodes with hairs which are dark brown, 2–6 cells long and with a spur at the base. Stipes wingless, 3–11 cm long. Fronds 8–35 cm long including the stipes. Lamina 3-pinnate-pinnatifid, submembranous to herbaceous, deltoid or lanceolate to very broadly ovate; the apex usually deflexed. Ultimate segments flat, cultrate to narrowly oblong, obtuse, denticulate. Veins free, not reaching the apex of each segment. Sori terminal on the short ultimate segments, immersed at the base. Involucre 0.8–1.2 mm long, 0.5–1 mm broad, orbicular to oval, entire, obconic at the base, 2-valved almost to the base. Receptacle included or slightly exserted. Widespread. RF, terrestrial or epiphytic, often on boulders Hymenophyllum bivalve
Involucre bivalvate deeply or to the base