Flora of North America species comparison

The characters used by J. A. Calder and D. B. O. Savile (1960) to separate var. porsildiana from var. pacifica overlap more significantly than do the characters that separate their subspecies, although inland populations of what has been called var. porsildiana gradually tend away from the morphology typical of coastal populations. Elven and Murray treated this taxon as a species distinct from Micranthes nelsoniana, because it apparently grows in stands mixed with other subspecies of M. nelsoniana without forming intermediates. The entire complex needs a thorough re-examination.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Variety cascadensis has sometimes been confused with Micranthes odontoloma, probably because the petal spots of var. cascadensis fade on herbarium specimens. The more deeply toothed leaves, the compactness of the inflorescence, and the tangled inflorescence hairs clearly distinguish it from M. odontoloma. This variety is present in the Coast and Cascade ranges.

(Discussion copyrighted by Flora of North America; reprinted with permission.)