One of the remarkable results of the expedition of Meriwether Lewis and William Clark in 1803-1806 was their extensive collection of western North America’s flora. The collections, mostly by Lewis, were the first extensive sampling of vegetation in the western territories newly acquired by the United States from France. Despite the loss of some specimens on the trail and subsequent to Lewis’s return from the expedition, a large number of plant specimens were presented to President Thomas Jefferson, the scientific mentor of the expedition. Today, after nearly two centuries and a circuitous path through the hands of a number of botanists at institutions in the U.S. and England, the bulk of the collection (226 specimen sheets) resides in the Lewis and Clark Herbarium of the Academy of Natural Sciences in Philadelphia. More than a third of the Lewis and Clark herbarium is type material, which includes three state flowers (Montana, Idaho, and Oregon) and a state grass (Montana). With the bicentennial of the Lewis and Clark Expedition approaching in 2003-6, we have assessed restoration needs of the collection. The condition of the specimens varies widely, from fragmentary to nearly intact plants in excellent shape. Ongoing efforts include repairs to sheets and specimens, re-housing specimens in custom archival holders and cabinets, and upgrading environmental conditions in storage rooms. In response to growing public interest in the Lewis and Clark Herbarium, a database and a series of digitized images of specimens will be made available to scientists, students, and the general public via the internet and print publications, as well as museum display. This restoration project is funded by federal grant from the Save America’s Treasures Program of the National Park Service, the Institute for Museum and Library Services, and private donors.

Key words: herbarium, historical botany, Lewis and Clark expedition