Pursh gives an expanded description and includes floral features taken from the inflorescences now preserved on the lectotype, a Lambert sheet. The type is dated 10 Apr 1806, and on 11 Apr Clark reports "the large leafed ash is in blume" (Moulton, 1991: 110). At this time the expedition was camped at the Cascades of the Columbia in Hood River Co., Oregon. The tree was well-known to Lewis as on 10 Feb 1806 he describes the species in some detail, considering it "a tree common to the Columbia river below the entrance of cataract river" (Moulton, 1990: 294). Both Lewis and Clark frequently referred to this species as an ash (Moulton, 1991: 14). (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:04/10/1806