Sciences / Plants / Lewis’s Plant Collection

Lewis’s Plant Collection

Specimen Presses

A botanist presses specimens of plants for study and comparison with other specimens of similar species that have been gathered at different times and places, worldwide. Meriwether Lewis knew that his studies in the field would be backed up by the most prominent cabinet—that is, laboratory—botanists of his day.

Among them was to be Frederick Pursh (1774-1820), a German botanist whom Lewis hired at Philadelphia in May of 1807, paying him a total of seventy dollars to assist him in preparing his collection for a planned but never written publication of his own.[1]Jackson, Letters, passim. Pursh examined 124 of Lewis’s specimens, verified or corrected Lewis’s descriptions, wrote many new “diagnoses,” and assigned names to the species that were new to science.[2]It is estimated that seventy or seventy-five specimens were new to science when Lewis collected them. Pursh honored Lewis by naming four new species after him: Linum lewisii (LEE-noom … Continue reading He also painted water colors of thirteen of those, and in 1814 included them all in his two-volume Flora Americae Septentrionalis (FLO-ruh a-MAY-ree-kay sep-TEN-tree-oh-NAL-iss; Plants of North America).

Botanical Collector

A botanical collector like Meriwether Lewis had to begin the process of preserving his specimens as soon as possible after picking them, to forestall wilting and shriveling. The field botanist must place the leaves, stems, flowers, fruits, and roots on sheets of mounting paper with the utmost care and foresight. The whole point is to preserve every specimen in a way that will enable the cabinet botanist to examine minute details that will facilitate the writing of a definitive analysis of each specimen. Immediately, each mount must be covered with a sheet of soft, loose-textured, highly absorbent bibulous (Latin for “drinking”) or “blotter” paper, in order to draw all moisture out of the specimen. In some cases a discreet dissection may be necessary to provide maximum value to the collection. A memorandum is added containing the date and place the specimen was found, perhaps with a very brief description including known uses of the plant, and the collector’s name. Stacks of specimen mounts and blotter papers are weighted down or tied together tightly, then monitored frequently until the drying is complete.

The Corps of Discovery’s Lewis was a conscientious field botanist. The collector must monitor the drying process carefully including daily awareness of ambient temperature and humidity to be sure the specimens remain intact and free from mold or decay and to guard against invading insects. If possible, the specimen must be exposed occasionally to warm sunlight and dry air. This must have been a serious challenge to Lewis under the field conditions he endured from day to day. It certainly was at Fort Clatsop, where the average daily humidity probably ranged from 70 to 90 percent, and it rained all but six days between their arrival at the coast and their departure on 23 March 1806. In short, until the specimens are deposited in a secure collection facility known as a herbarium, botanizing is a tedious, time-consuming procedure which demands close, periodic attention.

Sensory Observations

Even on the toughest days of the expedition, Lewis somehow found time to observe plants along the way. However, his major periods of systematic work evidently were at Fort Mandan, Fort Clatsop, and Long Camp.

The total number of specimens he collected is not known, but it is certain that all those he acquired between Fort Mandan and the Great Falls of the Missouri were destroyed when high water in the spring of 1806 flooded the underground cache where they had been stored. Some more went astray after the expedition was over; others were eventually destroyed by beetles. For many years the collection was scattered and generally ignored. Not until 1896 were most of the known sheets assembled in one collection at the Academy of Natural Sciences in Philadelphia, and not until 1966 was it subjected to a comprehensive, detailed study.[3]That study, still a major milestone in the literature, is Paul Russell Cutright’s Lewis and Clark, Pioneering Naturalists (Lincoln: University of Nebraska Press, 1969).

Also, we don’t know precisely what methods or materials Lewis used to preserve plant specimens. He might have used presses such as the one pictured here on the previous page, or else books of blotting paper and blank sheets. We do know that all the existing specimens have been remounted at some time in the past two hundred years, and that of the 226 botanical sheets now in the Lewis and Clark Herbarium at the Academy only 34 have their original labels in Lewis’s handwriting.

The process of pressing specimens preserves only the outlines, textures and skeletal structures of plants, so Lewis also took pains to write notes about their colors and tactile qualities, and often the aromas and flavors. Thus it is possible, by reading his often minutely detailed journal entries about plants, to appreciate the full scope and intensity of his concentration, the breadth of his awareness, and depth of his curiosity.

Meriwether Lewis made every step of the journey with all of his senses working all of the time. So, of course, did his co-captain and their men, so far as we can tell. The lessons of the Lewis and Clark Expedition are less about adventure, conquest, or commerce, than about concentration and awareness. These are particularly important values to cultivate in this age when most of us are artificially over-stimulated during almost every moment of our waking hours.

Related Pages

Notes

Notes
1 Jackson, Letters, passim.
2 It is estimated that seventy or seventy-five specimens were new to science when Lewis collected them. Pursh honored Lewis by naming four new species after him: Linum lewisii (LEE-noom loo-WEE-see-eye; Lewis’s wild flax), Mimulus lewisii (MIM-oo-luss loo-WEE-see-eye; Lewis’s monkey flower), Philadelphus lewisii (fill-uh-DELL-fuss loo-WEE-see-eye; Lewis’s syringa–si-RING-guh); and Lewisia rediviva (reh-dee-VEE-vuh; bitterroot).
3 That study, still a major milestone in the literature, is Paul Russell Cutright’s Lewis and Clark, Pioneering Naturalists (Lincoln: University of Nebraska Press, 1969).

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Discover More

  • The Lewis and Clark Expedition: Day by Day by Gary E. Moulton (University of Nebraska Press, 2018). The story in prose, 14 May 1804–23 September 1806.
  • The Lewis and Clark Journals: An American Epic of Discovery (abridged) by Gary E. Moulton (University of Nebraska Press, 2003). Selected journal excerpts, 14 May 1804–23 September 1806.
  • The Lewis and Clark Journals. by Gary E. Moulton (University of Nebraska Press, 1983–2001). The complete story in 13 volumes.