Robinson and Greenman did not suggest a name for this collection. However, Meehan (1898: 29) refers the sterile specimen to Cymopteris campestris Nutt. ex Torr. & A. Gray (Fl. N. Amer. 1: 624. 1840), a synonym of C. acaulis (Pursh) Raf. (Herb. Raf.: 40. 1833). This species, described by Pursh as Selinum acaule (1813: 732) and based on a Bradbury collection (PH-Lambert!), occurs primarily on the Great Plains but extends westward mainly to the Snake River Plains and just to the north in the montane valleys of southern Idaho. As the specimen was gathered on 29 Apr 1806 while the expedition was camped on the north bank of the Walla Walla River in Walla Walla Co., Washington (Moulton, 1991: 186), Meehan's identification is unlikely. On this date Lewis says "we purchased Some deer and chappellell this morning" (Moulton, 1991: 183), and on the label there is the note "The natives calld it Shappalell." It is possible, in this instance, that the collector of this specimen was a Native American rather than Meriwether Lewis. (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:04/29/1806