Lewis's Bitterroot Specimen

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Figure 7

All that is left of Lewis's specimen

To read the labels, point to the image.

The Academy of Natural Sciences of Philadelphia

The "T.M." in parentheses stands for Thomas Meehan (1826-1901), a botanist at the Academy of Natural Sciences who, in the late 1890s, found many of Lewis's specimens at the American Philosophical Society, where they had lain untouched and forgotten for three-quarters of a century. He moved them to the Academy's collection, mounted them, and in 1898 published the first list of the Lewis and Clark Herbarium. He attests by his initials that it is he who has labeled these few remains of Lewis's specimen–parts of a flower or two–which Frederick Traugott Pursh (1774–1820) had named Lewisia rediviva. Pursh was the young German botanist and former curator for the Philadelphia naturalist Benjamin Smith Barton. In 1807 Lewis entrusted his entire collection to Pursh for organization, classification, and entry into the corpus of contemporary botanical literature.

The phrase "Near Clark's R. Jul. 1st 1806 Lewis"–written by Frederick Pursh–relates that Lewis collected the specimen on July 1, 1806 in the vicinity of Travelers' Rest near the river that Lewis had named for his "worthy friend and fellow traveller Capt. Clark," but is now called the Bitterroot River. Gary Moulton believes that Lewis's journal entry for July second suggests that he might have collected it on that day instead: "I found several other uncommon plants specemines of which I preserved." But that's of minor importance.

The next sentence, also in the handwriting of Frederick Pursh, states first that the calyx, or group of sepals, consists of sometimes six, sometimes seven leaves. In the photograph the sepals are the pale leaves behind the pink petals. The corolla consists of "many pedals" (i.e., petals) and many "Tamina" (stamens). The stamens in the center, surrounded by the pink petals, are the male organs of the flower; they are topped by what Pursh called "Capsula," but now are called anthers. Meehan may have added Pursh's name to this label. The white envelope at upper right is the "packet" that contained pieces of the plant that have dropped off of the specimen at some time.


Figure 8

The flower that Frederic Pursh futilely
tried his best to imagine.

white bitterroot flower

© Stan Shebs, University of California Botanical Garden, Berkeley

At lower left are six buds, with the upper margins of their green sepals tinged with red.

Why is there no root, stem, sepal or leaf accompanying the bedraggled petals? Pursh answered that question in his comment on the plant in his book, Flora Americae Septentrionalis (1814):

This elegant plant would be a very desirable addition to the ornamental perennials, since, if once introduced, it would be easily kept and propagated, as the following circumstance will clearly prove. The specimen with roots taken out of the Herbarium of M. Lewis, Esq. was planted by Mr. M'Mahon of Philadelphia, and vegetated for more than one year: but some accident happening to it, I had not the pleasure of seeing it in flower.1

Pursh's reference was to the Irish-American horticulturist Bernard McMahon (1775-1816), who emigrated to America in 1796.2 In 1806 Thomas Jefferson named Pursh as one of two nurserymen to grow the seeds and roots brought back by Lewis and Clark, and it was McMahon who recommended him as the illustrator for Lewis's proposed book of botanical discoveries. It is thought that the "accident" he referred to was actually the well-meaning McMahon's excess of care and attention, which led him to over-water the dormant root, unaware that it belonged to a dryland species which still held enough moisture to enable its rejuvenation. Evidently McMahon discarded the remains.

Whatever the cause, McMahon evidently discarded the remains, so the alien species Lewisia rediviva had to hold its secrets for another half-century before its image could seduce curious eyes. Meanwhile, the only alternative was Pursh's dispassionate "diagnosis," a 72-word paragraph consisting of terse answers to ten key questions that its author might have discussed in a conversation with Lewis himself. However, it would have been of no use to anyone but another well educated botanist, because it was written in botanical Latin.3 Years passed–49 of them to be exact–while the small envelope containing the pitiful remains of the plant Pursh had named for him languished in the herbarium at the Royal Gardens of Kew, in a suburb of London, where Pursh had left them.

Figure 9

First Picture

To read the details, point to the image.

Scientific illustration of a plant with pink petals and long skinny roots

Missouri Botanical Garden, Peter H. Raven Library, via Biodiversity Heritage Library

1. Flora Americae septentrionalis, 2 vols. (London: White, Cochrane, and Co., 1814), No. 437, 2:368.

2. McMahon's principal achievement as a botanist was his initial authorship of The American Gardener's Calendar: Adapted to the Climates and Seasons of the United States, which was published annually from 1806 until 1857. Allen Lacy, "Bernard McMahon's Declaration of Independence," in Farther Afield: A Gardener's Excursions (New York: Macmillan, 1986).

3. As a botanical term, a diagnosis is a paragraph of aphoristic statements in the ablative case which describe the most distinguishing features of a plant, expressed in a blend of classical Latin with latinized words from Greek, English and many other languages, now collectively known as "botanical Latin." About 80 per cent of all generic names (such as Lewisia) and 30 per cent of specific epithets are from languages other than Latin and Greek. As the worldwide lingua franca of botanical science, its lexicon and grammatical rules are strictly governed and enforced by the ICN, or International Code of Nomenclature for algae, fungi, and plants, founded in 1905 after a long and tortuous search for clarity and simplicity. For example, with the publication of his Systema Naturae in 1735, Carl Linnæus had chosen to limit his diagnoses to a maximum of 12 words in the interest of brevity and convenience, but by 1814–coincidentally the year of publication of Nicholas Biddle's paraphrase of the journals of Lewis and Clark–the science of botany had gained so much momentum that the 80-year-old limitation was a burden on the science, which accounts for Pursh's 72-word descriptive document. In 2011, at the 18th International Botanical Congress, the historic requirement that the validating diagnosis must be in Latin was changed to allow new names to be validated with diagnoses in English. William T. Stearn, Botanical Latin: History, Grammar, Syntax, Terminology and Vocabulary, 4th ed. (Trowbridge, England: David & Charles Publishers, 1993), passim.