Characters: rhizomes creeping to suberect, bearing hairs; leaves determinate, mostly hemidimorphic or dimorphic; veins free, dichotomous, occasionally casually anastomosing; sporangia usually on a basal pair (sometimes more than two pinnae, or all pinnae modified and fertile) of skeletonized, highly modified, often erect pinnae; spores128–256 per sporangium, tetrahedral, with strongly parallel ridges (Tryon & Lugardon, 1991); gametophytes green, cordate, surficial; x = 38.
Distribution
Terrestrial; primarily New World, but a few spp. in Africa, India, and islands in Indian Ocean.
