A new species of Cymopterus (Apiaceae) from the Rocky Mountain region, U.S.A.

Cymopterus constancei is described as new from mostly western portions of Wyoming, Colorado, and New Mexico and from eastern Utah and Arizona. It has been confused withC. bulbosus A. Nelson but differs in several features of its bractlets, phenology, and habitat. The novelty is among the earliest of the native flora to bloom and is quite uniform morphologically. The number of collections encountered exceeds 200, a fourfold increase, in the past 22 years.