Description from Flora of China
Plants evergreen, medium-sized. Rhizomes short, ascending, bearing remaining stipe bases and dense thick roots, clothed with dark brown ovate-lanceolate scales at apex. Fronds approximate; fertile fronds: rachis grooved adaxially, glabrate; lamina pinnate-pinnatifid; pinnae pinnatipartite, up to 30 pairs, subopposite, spreading, sessile, ca. 1 cm apart (lower pinnae more widely apart). Veinlets 3-5 pairs, simple but basal veins frequently forked, oblique, reaching margins of lobes. Sori orbicular, single per pinna lobe, abaxial on basal acroscopic veins, close to costae; indusia pale green, broadly ovate or orbicular, thinly membranous, fugacious, basiscopic to receptacle, inferior (i.e., hidden by sporangia), partly covering sori when young, hidden by sporangia at maturity, persistent; annulus consisting of 12 or 13 thick-walled cells. Spores dark brown, bean-shaped, perispore with dense conical spines.
Cystoathyrium is similar to Athyrium and Cystopteris. It differs from Athyrium by the rhizome shortly ascending, glabrate, the stipe base not beak-shaped, the spore surface with conical spines, and the indusia basiscopic and inferior. It also differs from Cystopteris by the stipe short compared to the lamina, the lamina bipinnatifid, gradually narrowed toward the base, almost papery and evergreen, and the pinnae numerous, lanceolate and falcate.
? One species: China.
(Authors: Wang Zhongren (王中仁); Masahiro Kato)