Great Basin Naturalist


The 23 species and subspecies of Poa that occur in New Mexico are described in detail. Collection locations of these species in New Mexico are given in dot distribution maps. A descriptive key to the species of Poa that occur in Arizona, Colorado, Utah, Wyoming, and New Mexico, including general distribution for species not in New Mexico, is provided. Three new nomenclatural combinations are proposed: Poa arctica subsp. aperta; P. fendleriana subsp. longiligula; P. f. subsp. albescens. Subgeneric affinities of species of the southern Rocky Mountain region are indicated. Of the 25 species that occur within the region, the geographic affinities are circumpolar (P. alpina, P. arctica, P. glauca, P. interior, and P. leptocoma), Beringian (P. lettermanii, and P. pattersonii), Eurasian weeds (P. annua, P. bulbosa, P. compressa, P. palustris, P. pratensis (also circumpolar), and P. trivialis), Pacific Northwest (P. bolanderi, P. cusickii, P. nervosa, and P. stenantha), northern Great Plains (P. arida), southern Great Plains and South American Pampas (P. arachnifera), Great Basin–Californian (P. fendleriana and P. secunda), and Middle and Southern Rocky Mountain (P. bigelovii, P. curta, P. occidentalis, P. reflexa, and P. tracyi). The only native diploid Poa species known in the Southern Rocky Mountains, the contiguous United States, and southern Canada are P. lettermanii and P. occidentalis.