Poa canbyi is occasionally put into synonymy under P. secunda J. Presl (in K. Presl, Reliq. Haenk. 1: 271. 1830), a southern South American species that may or may not be the same as P. sandbergii Vasey (in Contr. U.S. Natl. Herb. 1: 276. 1893) of western North America. We follow Holmgren & Holmgren (Interm. Fl. 6: 248. 1977) in considering P. canbyi to be distinct from P. sandbergii and neither one a synonym of P. secunda. The type of Aira brevifolia was collected most probably along the trail toward Weippe Prairie northeast of Kamiah in Idaho Co., Idaho, on 10 Jun 1806. Currently the plant is common in the area as is the related P. sandbergii (Moulton, 1991: 337). (The Lewis & Clark Herbarium Digital Imagery Study Set, ANSP, 2002) On deposit at the Academy of Natural Sciences, Philadelphia Collected by:Meriwether Lewis & William Clark Collection date:06/10/1806