Stems compact; stem scales uniformly tan or somewhat darker near base, to 15 mm, margins ciliate-dentate to entire. Leaves 8--45 cm. Blade 1-pinnate to pinnate-pinnatifid, pinna pairs 20--45. Pinnae oblong to ovate, largest usually 7--15 mm, entire or asymmetrically lobed, lobes 2--7, broadly rounded, separated by shallow sinuses; abaxial scales concealing surface, lanceolate, usually 1--1.5 mm, ciliate with coarse marginal projections; adaxial scales abundant, mostly persistent, stellate to coarsely ciliate, elongate, attached at base, body mostly 5--7 cells wide. Sporangia containing 32 spores. n = 2 n = 87, apogamous. Sporulating summer--fall. Rocky hillsides and cliffs; usually on limestone or other calcareous substrates; 500--1800 m; Ariz., Nev., N.Mex., Okla., Tex.; n,c Mexico. R. H. Hevly (1965) hypothesized that Astrolepis integerrima was produced by hybridization between A . cochisensis and A . sinuata . Recent isozyme analyses (D. M. Benham 1989) indicate, however, that Astrolepis integerrima is an apogamous allotriploid hybrid between A . cochisensis and an unnamed Mexican taxon related to A . crassifolia (Houlston & T. Moore) D. M. Benham & Windham. Two morphologic forms exist in this taxon: one with essentially entire pinnae, and one (more common in the United States) with larger, asymmetrically lobed pinnae. The former might be confused with A . cochisensis on occasion, but the abundance of adaxial scales and the larger pinnae of A . integerrima should serve to distinguish these species. The lobed form of A . integerrima is superficially similar to A . windhamii , from which it is distinguished by the abundance and greater width of adaxial scales and the asymmetrical lobing of the pinnae.