As here circumscribed, Cheilanthes eatonii is a variable species comprising apogamous triploid and tetraploid cytotypes of unknown parentage. It includes plants previously identified as C . castanea and C . pinkavii (ined.). Type specimens of C . eatonii and C . castanea are quite distinct morphologically, but most plants here included within C. eatonii are intermediate between these two extremes (T. Reeves 1979). Because there is no clear morphologic break, C . castanea is placed here in synonymy under C . eatonii pending further study. Reports of hybridization between C . eatonii and C . villosa (D. B. Lellinger 1985) are based on specimens from western Texas and southern New Mexico that appear to be intermediate between these taxa in several characters. T. Reeves (1979) applied the name C . pinkavii to these specimens; that name has never been validly published. Formal recognition of this taxon is deferred pending completion of a biosystematic study of the C . eatonii complex as a whole.