ABSTRACT
Usually epiphytes, sometimes terrestrial and rupestral, occasionally faculta tive rheophytes. Rhizomes erect to long-creeping, nearly always bearing scales. Stipes glabrous or with hairs of various kinds, rarely with scales at the base. Laminae simple to tripinnatifid, glabrous or with hairs of various types. Veins free or rarely with occasional anastomoses, endings sometimes marked by hydathodes on adaxial surface of lamina. Sori exindusiate, on the abaxial surface of the lamina, sometimes sunken into it in pits, pouches or grooves which may be marginal, sometimes protected by the folded pinnae. Sporangia glabrous or with setae, the sporangial stalk with one row of cells at base and for most or all of its length. Spores with chlorophyll, sometimes germinating within the sporangium, usually globose-tetrahedral, rarely bilateral (not in Sri Lanka). A family of more than 20 genera, over 750 species, characteristic epiphytes of mossy montane forests in the wet tropics of both hemispheres, extending to north and south temperate zones, but markedly more common in the latter, represented in Sri Lanka by 7 genera and 22 species.
