Lewis 21 was collected near Decatur, Burt Co., Nebraska, on 10 Aug 1804 (Moulton, 1987a: 468). Only PH-LC 79 is annotated with an original Lewis label. Pursh annotated PH-LC 80 as Equisetum sylvaticum L. (Sp. Pl.: 1061. 1753), but did not mention the Lewis and Clark collections in his Flora (Pursh, 1813: 651). (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:08/10/1804