Plants terrestrial. Roots blackish, very narrow, tangled, practically glabrous. Stems upright to reclining; hairs few celled, uniseriate. Leaves all fertile or dimorphic with some sterile, lacking blades, mainly unbranched, long-petioled. Fertile blades folded and fistlike or pectinate, pinnate, segments (digits) arising along rachis on distal 3--10 mm; sterile leaves straight or often curling. Sporangia in 2 rows. Gametophytes growing mixed with mosses, green (photosynthetic), delicately filamentous, lacking hairs. x = 77, 94, 103.