Elkhorn, Clarkia pulchella
Since the only extant specimen of Clarkia pulchella collected by Lewis is the one on the preceding page, it is believed that Pursh based his painting on sketches he made for Lewis when the latter was in Philadelphia in 1807.1
1. James L. Reveal, Gary E. Moulton, and Alfred E. Schuyler, "The Lewis and Clark Collections of Vascular Plants: Names, Types, and Comments," Proceedings of the Academy of Natural Sciences of Philadelphia, Vol. 149 (29 January 1999), 15.