A few weeks ago, we learned about André Michaux, the great French botanist and explorer who was Thomas Jefferson’s first choice to explore the Missouri River to its source and find a route to the Pacific Ocean. As we found out, for a variety of reasons Michaux didn’t make it and ended up going back to France. The project languished for ten years until Jefferson became president and brought his dream of back to life, handing leadership of the western expedition to his personal secretary, Meriwether Lewis.
As outlined by the 1793 proposal Jefferson put before the American Philosophical Society, the goals of the Michaux expedition had been purely scientific. Michaux was one of the premier scientists of his generation in the field of botany; he’d received classical training in the French royal gardens and had years of field experience under his belt. Ten years later, Lewis and Clark’s expedition shared many of these scientific goals. But Lewis was no botanist — in contrast to Michaux, he was an army officer, with only a few years of formal schooling. So what business did he have trying to discover and classify new plants?
The answer is, quite a lot. For openers, Lewis had grown up with a veritable expert on local plants. His mother, Lucy Meriwether Lewis Marks, was a respected herb doctor in Albemarle County, Virginia, who treated patients with herbal remedies and “simples.” From his mother, Lewis learned to identify plants of medicinal value and how to use them for therapeutic purposes. An enthusiastic naturalist, Lewis developed, according to Thomas Jefferson, “a talent for observation which had led him to an accurate knowledge of the plants and animals of his own country.” This would turn out to be important, as Lewis needed to be able to tell what plants he found along the trail were “not of the U.S.”
Building on this foundation, Jefferson started Lewis on a rigorous course of botanical training as soon as he arrived at the White House in 1801 to take up his duties as Jefferson’s personal secretary. From April 1801 to July 1803, Lewis’s primary job duty was to prepare himself for the scientific aspects of the expedition. It is not known whether Jefferson outlined a formal course of study for Lewis, but Lewis’s subsequent botanical skill suggests that both of them took the studies very seriously. Lewis could not have had a more skilled instructor. A lifelong student of botany and natural history, Jefferson was personally familiar with the 130 plants he lists in his Notes on the State of Virginia, and upon returning from his post as Minister to France he had pioneered efforts to introduce beneficial European plants to the United States. Furthermore, he had a huge scientific library—undoubtedly the best in the United States at the time—and was untiring in his drive to experiment, observe, and inquire. Lewis had access to both Jefferson’s mind and his books.
Jefferson was also an expert on the relatively new Linnaean system for classifying plants. Developed by the Swedish naturalist Carl Linnaeus, this system provided a way to identify animals and plants uniquely with class, genus, and species designations. Lewis spent some time studying the Linnaean divisions. It is known that among the reference works Lewis took with him on the expedition were two titles on plant classification, An Illustration of the Sexual System of Linnaeus and An Illustration of the Termini Botanici of Linnaeus.
Lewis’s botanical training was rounded out by a visit with Dr. Benjamin Smith Barton during his crash course with the country’s leading scientific minds in Philadelphia during the spring of 1803. Dr. Barton was a professor of botany at the University of Pennsylvania, a friend of Jefferson’s, and the author of Elements of Botany: or Outlines of the Natural History of Vegetables, the first botany textbook produced in the United States. Lewis evidently got some training on how to preserve plant specimens from Barton and purchased the textbook as a reference to take with him on his trip.
So how well did Lewis perform as a botanist? While still not a scientist of the caliber of Jefferson, Barton, or Michaux, he was a careful, methodical, and competent observer of the plants he encountered on the trail. While he rarely attempted to name a plant with a full-fledged Latin name in the style of Linnaeus, he did have a very solid working knowledge of botanical terms for describing plants. Here is a case in point—Lewis’s description of the ragged robin, or “Clarkia pulchella:”
I met with a singular plant today in blume of which I preserved a specemine; it grows on the steep sides of the fertile hills near this place, the radix is fibrous, not much branched, annual, woody, white and nearly smooth. the stem is simple branching ascending, 2½ feet high celindric, villose and of a pale red colour. the branches are but few and those near it’s upper extremity. the extremities of the branches are flexable and are bent down near their extremities with the weight of the flowers. the leaf is sissile, scattered thinly, nearly linear tho’ somewhat widest in the middle, two inches in length absolutely entire, villose, obtusely pointed and of an ordinary green. above each leaf a small short branch protrudes, supporting a tissue of four or five smaller leaves of the same apeparance with those discribed. a leaf is placed underneath eah branch, and each flower. the calyx is a one flowered spathe. the corolla superior consists of four pale perple petals which are tripartite, the central lobe largest and all terminate obtusely; they are inserted with a long and narrow claw on the top of the germ, are long, smooth, & deciduous. there are two distinct sets of stamens the 1st or principal consist of four, the filaments of which are capillary, erect, inserted on the top of the germ alternately with the petals, equal short, membranous; the anthers are also four each being elivated with it’s fillament, they are linear and reather flat, erect sessile, cohering at the base, membranous, longitudinally furrowed, twise as long as the fillament naked, and of a pale perple colour. the second set of stamens are very minute are also four and placed within and opposite to the petals, these are scarcely persceptable while the 1st are large and conspicuous; the filaments are capillary equal, very short, white and smooth. the anthers are four, oblong, beaked, erect, cohering at the base, membranous, shorter than the fillaments, white naked and appear not to form pollen. there is one pistillum; the germ of which is also one, cilindric, villous, inferior, sessile, as long as the 1st stamens, and marked with 8 longitudinal furrows. the single style and stigma form a perfect monapetallous corolla only with this difference, that the style which elivates the stigma or limb is not a tube but solid tho’ it’s outer appearance is that of the tube of a monopetallous corolla swelling as it ascends and gliding in such manner into the limb that it cannot be said where the style ends, or the stigma begins; jointly they are as long as the corolla, white, the limb is four cleft, sauser shaped, and the margins of the lobes entire and rounded. this has the appearance of a monopetallous flower growing from the center of a four petalled corollar, which is rendered more conspicuous in consequence of the 1st being white and the latter of a pale perple. I regret very much that the seed of this plant are not yet ripe and it is proble will not be so during my residence in this neighbourhood.—
As Paul Russell Cutright observed, “Lewis’s description of this plant is positive evidence of what he could do graphically with root, stem, leaf, and flower in one hand and pen in the other.” Lewis described plants completely, including details of taste, smell, sight, and touch. Cutright notes that Lewis employed more than 30 botanical terms in this description, and over 150 in various descriptions of other plants throughout the journals.
As Lewis crossed the western part of the continent, he described as best he could the geographical range of the plants, their size and dimension, and speculated on which plants had commercial possibilities and might make suitable transplants to the East. He described in detail the fruits and roots the Corps of Discovery added to their diet, some of which saved the Corps from starvation. Lewis’s knowledge of plants was helpful in this respect: aside from gas from eating wapato roots, there is no record in the journals of anybody suffering from eating a poisonous plant. At times he treated himself and other members of the Expedition with medicinal simples for fever and pain.
Lewis diligently collected seeds and pressed plant specimens throughout the trip. Regrettably, many of these were left in a cache at the Great Falls that was ruined by floodwaters and never made it back East. In spite of this, Lewis brought back over 150 carefully preserved plant specimens from the latter partof the trip, at least half of which were new to science. This Lewis and Clark Herbarium still exists; it is owned by the American Philosophical Society and kept at the Academy of Natural Sciences in Philadelphia. Some of these plants bear Lewis’s name, as the Linnaean genus Lewisia and the species lewisii were created to honor what the explorer modestly referred to as his “slender botanical skill.”