Allosorus raddeanus (Fomin) Ching; Cryptogramma brunoniana Wallich ex Hooker & Greville var. raddeana (Fomin) Fraser-Jenkins; C. brunoniana var. sinensis (Christ) G. M. Zhang; C. crispa (Linnaeus) R. Brown ex Hooker var. sinensis Christ.
Rhizomes stout and erect; scales brown, lanceolate, membranous. Fronds tufted; stipe straw-colored, sparsely scaly proximally, stipe of sterile frond shorter, 4-5 cm, that of fertile frond 7-16 cm. Sterile fronds: lamina brownish green when dry, broadly ovate, 3-5 × 1.5-2 cm, 4-pinnate-pinnatifid, papery, glabrous on both surfaces; hydathodes obovate and not sunken below frond surface on dried specimens. Fertile fronds: lamina ovate or ovate-oblong, 4-6 × 1.5-3.5 cm, finely 3-pinnate to 3-pinnate-pinnatifid. Sterile pinnae 6 or 7 pairs, basal pair largest, ovate, 1.6-2.2 × 1.2-1.7 cm. Ultimate sterile segments linear or spatulate, apex rounded, one veinlet in each segment. Ultimate fertile segments linear at first, elliptic when mature, 3-5 × 1-2 mm, apex obtuse. Sori confluent and spreading over abaxial surface of fertile frond when mature. False indusia brown, linear, margins entire.
On rocks; 2600-4600 m. W Hubei, Shaanxi, NW and W Sichuan, Xizang, NW Yunnan [NW Nepal, Russia].
Cryptogramma raddeana has been treated as a variety or subspecies of C. brunoniana, but plastid DNA data resolve each of the two taxa as well-supported clades that are reciprocally monophyletic to one another and have a level of genetic differentiation similar to other interspecific divergences in the genus (Metzgar, unpubl. data). They also differ in slight but consistent morphological differences (e.g., lamina dissection, pinnule shape). Combined, this suggests that they are distinct though closely related species. Perceived intergradation between related taxa in Cryptogramma can be due either to formation of sterile hybrids (Alverson, Biosyst. Parsley-Ferns, MS thesis, Oregon State University. 1989) or to the presence of fronds that are developmentally intermediate between sterile and fertile fronds, which obscure the differences between taxa in frond dissection and segment shape (Hultén, Fl. Aleutian Islands. 397pp. 1937).
