rhizomes creeping, ascending, or suberect, bearing clathrate scales at apices and petiole bases (and sometimes other axes); petioles with back-to-back C-shaped vascular strands, these fusing distally into an X-shape; blades monomorphic, usually lacking acicular hairs on axes and/or lamina, often with microscopic clavate hairs; veins pinnate or forking, usually free, infrequently reticulate and then without included veinlets; sori elongate (linear) along the veins, not usually back-to-back on the same vein, usually with laterally attached, linear indusia; sporangial stalks long, 1-rowed; spores reniform, monolete, with a decidedly winged perine; x = 36 (mostly), but x = 38, 39in Hymenasplenium (Murakami, 1995), 38 in Boniniella.
Distribution
Terrestrial, epipetric, or epiphytic, subcosmopolitan, but most numerous in the tropics.
Systematic remarks
From one to ten genera (generic delimitation in doubt, in light of all recent molecular data)
