Pellaea glabella subsp. simplex
Taxon 26: 325. 1977.
Ultimate segments essentially glabrous; sporangia containing 32 spores; spores averaging 60–72 µm diam. n = 2n = 116, apogamous.
Phenology: Sporulating summer–fall.
Habitat: Calcareous cliffs and ledges, usually on limestone
Elevation: 900–3000 m
Alta., B.C., Ariz., Colo., Idaho, Mont., N.Mex., Utah, Wash., Wyo.
This western counterpart of Pellaea glabella subsp. glabella is an apogamous tetraploid. A. F. Tryon (1957) and D. B. Lellinger (1985) hypothesized that it might have arisen as a hybrid between the western diploid member of the P. glabella complex (here called subsp. occidentalis) and P. atropurpurea. G. J. Gastony (1988) has shown conclusively, however, that P. glabella subsp. simplex is an autopolyploid derivative of subsp. occidentalis and does not contain genes contributed by P. atropurpurea.