Erigeron parryi was described in 1890 from a single collection from southwest Montana. No additional collections were made during the following 90 years. Recent floristic treatments have synonomized E. parryi under E. ochroleucus. I used principal components and discriminant analyses of morphological characters to examine the relationship of E. parryi to its presumed closest relatives, E. ochroleucus, E. radicatus, and E. scribneri, in light of several populations discovered in the past 20 years. Erigeron parryi should be considered a distinct species. It can be readily distinguished from closely related species based on indument and caudex morphology. It is allopatric with E. ochroleucus and E. scribneri and ecologically separated from E. radicatus. Erigeron scribneri is intermediate between E. ochroleucus and E. radicatus and is probably best treated as a variety of one or the other of these species.
Lesica, P. 2005. The resurrection of Erigeron parryi (Asteraceae) Brittonia 57: 47-54.