"Like most people of his day, Meriwether Lewis (1774-1809) was knowledgeable about plants. His mother was an herbalist, & as an agriculturist he was interested in plants of economic importance. Thus, when Jefferson assigned Lewis the task of naturalist it was natural that Lewis would focus, as Jefferson instructed him, on medicinal plants, plants of economic value such as corn, wheat, grasses, fodder, & plants that would have been of horticulture interest, as Jefferson had a large garden & was very much interested in horticulture plants.
"For Jefferson, the decision not to send a true naturalist, but rather one that was semi-trained was both fortunate & unfortunate. For the botanical community the fact that Jefferson did not send a naturalist meant that only a few select specimens were collected. Nonetheless, the more than two hundred specimens that reached Philadelphia, from the activities of the Lewis & Clark Expedition, signified the richness of the flora of the Pacific Northwest & particularly the states of Oregon, Washington, Idaho & Western Montana.
"Lewis’s collection activities were limited to opportunities when he had a chance to collect. As captain he had many other duties besides looking for new plants. Thus it was, we know from his journals, that not only did he collect, but so did some of the other men. There are even indications that Sacagawea or Saka Kawea collected plants as well.
"Lewis's collecting activities were not described by him, but looking at contemporaries, it is clear that Lewis used a small hand press. This allowed him to collect small samples that he would then dry over a period of days. Because he had no other means of drying these plants other than sunshine he was very careful what he collected. For example; he avoided cactus & all kinds of succulent plants except for two—both sedums, or rock plants. He collected lots of grasses, because they were economically important as food. He collected crop plants that were grown by the native people. And he collected a bountiful number of wildflowers, particularly in 1806 as he crossed the Rocky Mountains.
"Some of the plants that Lewis collected were found along the Lolo Trail in late June of 1806, & then across Lewis & Clark Pass in early July of 1806. Many of those species are represented in his herbarium & may be seen even today along the Lewis & Clark Trail.
"Lewis's tendency was to collect specimens that he could, in a small sample, show all of the detail that he needed to show. Thus, he tended to collected plants in good flower & occasionally, if he felt it was important as a medicinal plant, in fruit, so he could then grow seeds from the plant once he returned the material to Philadelphia.
"Seeds were commonly collected in 1805 particularly along the Columbia River. Very few seeds were collected in 1806 on the return trip. Numerous specimens & seeds were collected as they ascended the Missouri River in 1804.
"Lewis's interest in the wildflowers of what we now call the Rocky Mountains was much as any individual's today. They are abundant & beautiful & easy to collect. The success of his collection resulted in the discovery of three new genera, one named for him, one named for Clark, & another named for the character of the plant. Several new species were collected. And, most that you see surrounding us here today were collected by Lewis & were named from his specimens.
"Lewis's plant press was probably in the form of a book. A very large book, probably twelve by eighteen inches. It may or may not have been bound on the one side. This is a traditional plant press that you find in China. It is made out of bamboo & consists of a flat strong surface that specimens can be placed in. Lewis used paper much like you used as a youngster in kindergarten. A kind of construction paper. It was folded in half & the specimen placed in between. Now, Lewis's paper was twelve by eighteen when folded, this is half that. You'll notice that the paper is absorbent. This way the specimen's moisture would go into the paper, be absorbed by the paper, & then the specimen could be slowly dried. But in drying, everyday Lewis had to open his press, remove the old pages that were damp, lay them in the sunshine, allow them to dry, & move his plants into new paper so they would continue to dry.
"Modern botany is quite different from Lewis's day. We use very large presses & in a good operation you'll run three to five presses, filling each during the course of a day. Each press consists of about room for one hundred different specimens. We are able to dry these very rapidly using what is known as a Holmgren drying frame, by putting a heat source underneath, a coleman stove or electric light bulbs. The heat rises through the corrugates, the holes in the corrugates, & will dry plants overnight, if not during the course of twenty-four hours.
"Today we are in Packer Meadow on the Clearwater National Forest. This was a lunch stop for the Lewis & Clark Expedition in late June of 1806. Very likely, because Lewis had collected so many plants coming up the Lolo Trail, he took time out during that lunch break to work his plant specimens. Lewis would open his press & open up, in his case, each individual page of his press. Coming on to his first specimen he would then take a look at it, make sure that the leaves were flat & that all the diagnostic characters of the flowers were shown so they could be studied. He would repeat this for each specimen &, if necessary, would replace the paper with new paper.
"This is the common camas that Lewis & his men experienced in 1805. Tradition says that Lewis & Clark & his men became ill from eating the bulbs. That's probably not true. More likely the culprit was salmonella poisoning associated with the dried—poorly dried—salmon.
"It's interesting that Lewis collected the Canadian Dogwood or Cornus candadensis. This is a plant he knew well from Virginia. It's interesting to speculate whether he collected it because he knew it, collected it because he wanted to show that something from Virginia also grew in the Rocky Mountains, or what. Maybe he was homesick. The other specimen that I have here is the new genus of mariposa lily collected by Lewis & Clark along the Lolo Trail in Idaho & Montana in late June & early July. This is Calicortis pulcella, or "beautiful mariposa lily".
"Two specimens that Lewis would have handled during the stop in Packer Meadow is a skyrocket, this little high elevation blue flower which occurs near the summit, & also near the summit is this species of menzesia, named for the surgeon naturalist Archibald Menzies who preceded Lewis & Clark in the Pacific Northwest in the late 1790's. Menzies collected only along the coast, & this is one of those species that goes from the coast to the high mountains in the Rockies. Lewis was very judicious in what he collected. He made only small specimens. Even though this is a large shrub he would have collected only a little bit of it. The reason is simple, someone had to carry it to Philadelphia.
"A specimen has three dimensions: odor, good color & a feel of surroundings, not seen on a flattened dried specimen. And yet, all the technical details necessary for identification, the number of petals, sepals, stamens, the condition of the ovary & fruit, the leaves, even the habitat of the plant can be nicely preserved in any specimen. Occasionally if you have a tree or a shrub it is necessary to make notes indicating the size of the tree or the shrub. This Lewis did on occasions, & we now have his original notes to go by.
"This plant has bulbs. They are thick & fleshy. Drying one of those would be very difficult. Thus, Lewis rarely collected any succulent plant & certainly none of the bulbs that would require days, if not years, to dry. In fact, the reason Lewisia rediviva is called Lewisia rediviva is the genus name honors Lewis but the species name, or epithet, rediviva means revived. That's because the specimen that Lewis made at Travelers' Rest July 1, 1806, was still alive when it reached Philadelphia in September of that year. The specimen that Lewis returned to Philadelphia with, that would later be called Lewisia rediviva, was removed from his collection paper & grown in Philadelphia. It was observed for almost a full year before it suddenly died. Very likely, as everyone knows, over watering plants can be dangerous & deadly, & certainly that's the case with Lewisia.
"Meriwether Lewis described his plants in his journals. He had his training from Barton in Philadelphia, but he also had with him two volumes of John Miller's book on Linnaeus's system of botany. One was an illustration of the terminology of the Linnaean system & the other was on the system itself. So what Lewis could do is, he could use these two books & write his descriptions in a very technical way, so botanists who read the journals would be able to have that information.
"As a naturalist, Lewis has been fairly highly regarded by the modern community. He worked under trying & difficult situations. While it is clear that he was only able to devote a portion of his time to the effort, what he did is widely respected. It should be noted however, that in 1811, Thomas Nuttall of England, went up the Missouri River & collected several hundred more specimens than Lewis & Clark did in 1804. In 1834 & 1835 Thomas Nuttall came to the Rocky Mountains of Idaho, Oregon & Washington & collected hundreds of specimens. Many of the plants that Lewis & Clark found, that were not named in Lewis' time were subsequently named by Thomas Nuttall from his own collections."
By James L. Reveal, Professor Emeritus, Botany University of Maryland, Supported in part by a grant from the Idaho Governor's Lewis & Clark Trail Committee