Pursh (1813: 647) calls this Juniperus excelsa Willd. (Sp. Pl. 4: 852. 1805) and Meehan (1898: 46) reports it as J. occidentalis Hook. (Fl. Bor.-Amer. 2: 166. 1838). Lewis 58 was collected along the bluffs above the Missouri River on 2 Oct 1804 near the Sully-Potter Co. line in South Dakota where Lewis gathered several other prairie shrubs and low trees (Moulton, 1987a: 470). The specimens must have been collected with some caution that day as there were various encounters with Indians and the party spent the night on an island (1987a: 138-140). Lewis probably did not venture too far from the rest of the men as they worked their boats up stream. The collection locality is just east of the known present-day distribution of the species (Little, 1971: map 30). The trees must have been impressive as Lewis says "some of them [are] 6 feet in the girth." There is some confusion with regard to the label data and the location published by Pursh. In print he has "On the banks of the waters of the Rocky-mountains." We are not certain what Pursh means as there is nothing to suggest the tree came from the mountains. However, Lewis certainly saw the species in the Rocky Mountains and perhaps told Pursh of its distribution. It is also possible that Pursh is referring to the provenance of the waters, which originate in the Rocky Mountains. (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:10/02/1804