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Plants terrestrial. Roots occasionally branching laterally, yellowish to black, 0.5--2 mm diam., smooth or with corky ridges, not proliferous. Stems upright, forming caudex to 5 mm thick; gemmae absent or minute, spheric. Trophophores ascending to perpendicular to stem, sessile or stalked; blades linear, oblong, or deltate, simple to 5-pinnate, 4--25 × 1--35 cm. Pinnae (reduced to segments in many species) spreading to ascending, fan-shaped to lanceolate to linear; margins entire to dentate to lacerate, apex rounded or acute; veins free, arranged like ribs of fan or pinnate. Sporophores normally 1 per leaf, 1--3-pinnate, long-stalked, borne at ground level to high on common stalk. Sporangial clusters with sporangia sessile to short-stalked, almost completely exposed, borne in 2 rows on pinnate (except in very small plants) sporophore branches. Gametophytes broadly ovate, unbranched, 1--3 × 1--10 mm. x =44, 45, 92.
Terrestrial herbaceous ferns with a short erect undivided subterranean rhizome, producing numerous fleshy roots which are contractile in some species; apex protected by old persistent leaf bases. Fronds solitary or rarely 2 per year; common stipe producing a sterile lamina and a sporophore; sterile lamina sessile or petiolate, 1–3-pinnate or palmately divided: veins free, dichotomous. Sporophore on a long petiole, 1–3-pinnate; 2 halves usually folded together; sporangia large, free, subsessile, globose, dehiscing horizontally. Spores reticulate or verrucose, yellow.
Lvs glabrous or sometimes with simple hairs; blades mostly pinnately or ternate-pinnately or subpalmately compound or dissected, seldom simple, the veins forked and free; sporophore 1–several times pinnate, the numerous sporangia short-stalked and free, spores 1500–2000. 30+, cosmop. Depauperate or juvenile plants of related spp. are scarcely to be distinguished; spp. 5–10 are morphologically confluent, but said to be genetically distinct.
Sporangia coriac., in two close marginal rows, mostly sessile, globular, opening transversely. Roots rather stout, ∞, clustered on erect rhizome. Lf-segs fleshy, pinnately to ternately divided or decompound. Genus subcosmopolitan, of some 35 spp.
Fertile segment of frond amply branched with spreading branches; sterile segment (in Malaysian species) pinnately branched with many small divisions
