During the winter of 1804, Captain Meriwether Lewis, the Expedition’s naturalist and a fervent student of plants since childhood, spent many hours collecting, preserving, and describing hundreds of plant specimens during the journey. Of the specimens that survived the Expedition, 178 were new to science. At least one plant, arctostaphylos uva-ursil, was collected at Fort Mandan, though because the Expedition arrived in this area in late October most plants were hard to identify. An invoice of articles sent from Fort Mandan to President Jefferson included a specimen of a plant and some of its roots that were highly prized by Native people as an effective remedy for the bite of a rattlesnake or a mad dog; this plant is thought to have been the narrow leaf purple coneflower, echinacea angustifolia. Lewis’s mother was a herbal healer and knew what roots and plants helped in different cases, and he used what he had learned from her on the Expedition, noting the potential medicinal use of many of the plants collected. His preservation techniques were outstanding, and most of his specimens remain in the Lewis and Clark Herbarium of the Academy of Natural Sciences of Philadelphia.