Description from Flora of China
Allosorus Bernhardi; Mildella Trevisan.
Plants terrestrial or on rocks. Rhizomes erect and short, less commonly decumbent or creeping, siphonostelic; scales concolorous or bicolorous, brown to chestnut-black, sometimes with a pale border, subulate to lanceolate. Fronds monomorphic, tufted, clustered, or relatively closely spaced along rhizome. Stipe chestnut-colored to black, sometimes lustrous, terete or grooved adaxially, with 1 vascular bundle at base, sparsely to densely scaly and hairy, at least proximally or when young, sometimes glabrescent at maturity. Lamina lanceolate, oblong-lanceolate, oblong, or ovate-pentagonal, 1-3-pinnate-pinnatifid, herbaceous or papery to leathery, glabrous or hairy on both surfaces. Ultimate segments sessile to shortly stalked, broadly or narrowly attached, variously shaped. Veins of ultimate segments free (but sometimes obscure), unbranched or forked distally. Sori orbicular, at vein tips, often confluent at maturity. False indusia absent or formed by reflexed margins, interrupted to continuous, sometimes somewhat modified, margins entire, erose, serrulate, or ciliate. Spores globose-tetrahedral, perispore granular, pseudo-reticulate, cristate, or rarely rugulate. x = 28, 29, 30.
As treated here, the genus Cheilanthes is an unnatural assemblage that includes members of two groups. The genera Cheilosoria Trevisan and Notholaena R. Brown are typified by New World species, and these names have been misapplied to Asian taxa. The Asian species that have been treated under these names are part of a lineage that includes the species of Aleuritopteris, according to several independent studies of molecular phylogeny. These taxa are included in Cheilanthes for convenience, both because the necessary combinations in Aleuritopteris have not been published and because taxonomic relationships within the Aleuritopteris lineage are still poorly understood. Species formerly included in Mildella, which sometimes have been misclassified in Pellaea, also are members of this lineage. On the other hand, C. tenuifolia is part of Cheilanthes s.s., a group of ca. 35 species with centers of diversity in Australia, Africa (South Africa), and South America.
More than 100 species: Africa, Asia, Australia, Europe, Oceania, South America; 17 species (seven endemic) in China.
(Authors: Zhang Gangmin (张钢民); George Yatskievych)