Plants terrestrial, on rock, or rarely epiphytic. Stems erect or nearly erect, rarely long-creeping, scaly. Steles radially symmetric or dorsiventral (with structurally distinct abaxial and adaxial aspects) dictyosteles. Leaves monomorphic, rarely almost dimorphic with fertile leaves taller and more erect than sterile ones. Petioles with 1 vascular bundle X-shaped in cross section or with 2 vascular bundles back to back and C-shaped. Blades extremely diverse, simple to 4-pinnate, commonly with tiny glandular hairs and a few linear scales, rarely with spreading hairs. Veins free to anastomosing. Sori borne on veins, ± lunate to linear. Indusia usually present, shape conforming to sorus and originating along 1 side of sorus. Sporangia with stalk of 1 row of cells, annulus vertical, interrupted by sporangial stalk. Spores monolete; perispore typically winged, spiny, reticulate, or perforate. Gametophytes surficial, green, cordate.