Plants terrestrial or epipetric, sometimes rheophytic; roots blackish, wiry, inserted radially, non-proliferous; rhizomes short- to long-creeping, or suberect to erect, branched or more commonly unbranched, bearing scales, and sometimes golden hairs similar to the root hairs (e.g., Athyrium skinneri (Baker) Diels); rhizome scales lanceolate, not or only weakly clathrate, the margins usually non-glandular, sometimes glandular (some Deparia), without distinct pubescence, entire or dentate, when present the teeth commonly formed by two adjacent cells (Diplazium); leaves sometimes internally mucilaginous (some Deparia and Diplazium spp., particularly those treated as Callipteris), not externally covered in mucilage during any stage of development, green in Diplazium and Deparia, the petiole and rachis frequently with a pink hue in Athyrium presumably due to anthocyanins, monomorphic, spirally arranged or sometimes distichous and dorsal (e.g., Athyrium skinneri), occasionally bulbiferous, closely to distantly spaced, sparsely to moderately scaly and occasionally pubescent (Athyrium, Diplazium) or with a reduction series beginning with scales at the base of the leaf that gradually reduce  to catenate hairs distally (Deparia, some Diplazium); petioles castaneous, stramineous, or proximally darkened, often with a proximal thickening forming trophopods that may be starch-filled (Athyrium, Cornopteris, Diplazium), often with conspicuously elaborated aerophores (elsewhere termed pneumatophores; Cornopteris, some Athyrium, some Deparia), the bases usually persistent, rarely articulate to the rhizome (e.g., Anisocampium and Athyrium skinneri), and sometimes with golden hairs similar to the root hairs (e.g., Athyrium skinneri); petiolar vascular bundles two (rarely more; Kato, 1972), each with hippocampiform xylem, the bundles distally uniting to form a single U- or V-shaped bundle; laminae soft-herbaceous to coriaceous, simple to 3-pinnate-pinnatifid, the apex usually pinnatifid or non-conform, sometimes conform in Diplazium, the  leaf marginal cells differentiated into nodulose hyaline cells or not; pinna axes not articulate, sometimes muricate (Diplazium), sulcate adaxially, lacking a free central ridge; the rachis grooves V-shaped (Anisocampium, Athyrium,  Cornopteris) or U-shaped (Deparia, Diplazium), continuous (Anisocampium, Athyrium, Cornopteris, most Diplazium) or not continuous (Deparia, some Diplazium), the sulcus wall of the rachis usually continuing as a prominent ridge onto the sulcus wall of the costa (but not in Deparia); veins free or sometimes anastomosing (Deparia species treated as Dictyodroma, and some Diplazium), the areoles without free included veinlets, usually terminating before the leaf margin, the vein endings slightly raised and expanded, or forming hydathodes, or not differentiated; sori usually elongate, sometimes round, not  terminal, on top of the vein, or along one side, singular or paired back-to-back along the same vein, or hooked in most  Athyrium (i.e., paired back-to-back and crossing over the vein at one end in J- or U-shapes), or rarely sori marginal (e.g.,  Deparia prolifera (Kaulf.) Hook. & Grev.), at the tips of vein endings, usually indusiate; soral receptacle flat; indusia lateral,  vaulted or essentially flat, glabrous or glandular, opening along the lateral margin; sporangia with stalks two or three cells wide in the middle; spores monolete, non-chlorophyllous, brown, the perispore nearly plain to coarsely tuberculate, echinate, or folded, the folds short and low, forming a rugate surface, or broad and wing-like; chromosome base numbers x = 40 (Athyrium, Deparia, some Cornopteris; Manton & Sledge, 1954; Kato, 1979; Sano & al., 2000a, b; Liu & al., 2011), or 41 (Diplazium, some Cornopteris; Manton & Sledge, 1954; Kato, 1979; Dawson & al., 2000). Reports of x = 41 for Deparia require confirmation (reviewed in Sano & al., 2000a), and reports for individual Cornopteris species are occasionally inconsistent (alternating between x = 40 and x = 41), indicating that further cytological study is needed.

The family Athyriaceae includes about 600 species in 5 genera. Several genera of Athyriaceae can be diagnosed by unique  or rare character states. However, character state reversals and homoplasy render these characters imperfect diagnostics for the family. 

Global distribution of Athyriaceae

CAUTION: GBIF records include introduced and cultivated plants. In addition, GBIF may follow a different taxonomic interpretation from that adopted in the treatments presented here. For all three reasons, the distribution shown may differ from statements presented here about a taxon's native distribution.

Rothfels C.J., M.A. Sundue, L-Y. Kuo, A. Larsson, M. Kato, E. Schuettpelz & K.M. Pryer. (2012) A revised family-level classification for eupolypod II ferns (Polypodiidae: Polypodiales) Taxon 61: 515-533.

Smith A.R., K.M. Pryer E. Schuettpelz, P. Korall, H. Schneider & P.G. Wolf. (2006) A classification for extant ferns. Taxon 55: 705-731.