Athyriaceae Alston

Plants terrestrial or epilithic, small to medium-sized, sometimes large. Rhizome long or shortly creeping, ascending or erect, rarely short treelike, dictyostelic, scaly; scales entire or toothed, tooth consisting of 2 adjacent upturned ends of marginal cells, basifixed, rarely pseudopeltate. Stipe supplied by 2 vascular strands with xylem seahorse-shaped in cross section and upward united into U-shaped strand, scaly, also hairy or glabrate, hairs unicellular or multicellular, glandular or eglandular. Rachis, costae, and costules grooved adaxially, grooves of costae and costules confluent to those of lower order frond axes or interrupted by ridges between grooves, scaly, hairy, or glabrate; hairs unicellular or multicellular, glandular or eglandular; spines continued from ridges, or short fleshy projections in grooves, at base of costae, costules, and midribs adaxially, or spines and projections absent. Lamina variously dissected, simple to 3-pinnate, pinnatifid or with terminal pinna similar to lateral pinnae, apex narrowed. Veins free or anastomosing with polygonal areoles or with successive veins from adjacent midribs united to excurrent veins between 2 rows of rhomboid areoles. Sori various, linear, J-shaped, horseshoe-shaped, orbicular-reniform, or orbicular, indusiate or exindusiate; indusia inferior entirely or proximally to receptacle, or lateral, various in shape, sack-shaped, cup-shaped, saucer-shaped, platelike, elongate, J-shaped, horseshoe-shaped, or orbicular-reniform. Spores bilateral, ellipsoid, covered by perispore.