Lewis's Beargrass Specimen

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Lewis's Herbarium Specimen

Beargrass, Xerophyllum tenax

To read the text, click each label.

Interactive photo of a dried plant with large, white inflorescenceLabelAnnotation 1Annotation 2Annotation 3Annotation 4Annotation 5Annotation 6

Academy of Natural Sciences, Philadelphia

Beargrass Inflorescence


Photo from The Lewis and Clark Herbarium;: Images of the
Plants Seen or Collected by Meriwether Lewis and William Clark, 1804–1806,
at http://www.life.umd.edu/emeritus/Reveal/pbio/LnC/fam3.html.
Used by permission of The Academy of Natural Sciences, Philadelphia.

On average, depending on various factors, a beargrass inflorescence may contain between 50 and 250 flowers.

Many of the dried specimens Lewis and Clark gathered on their 1804-1806 expedition were used by the Saxon botanist Frederick Pursh to characterize those he felt were new to science. Herbarium specimens—dried and pressed specimens mounted on paper together with information as to their origins—serve as "vouchers," or reference resources, for comparison with other specimens collected at a later time or in a different place.

When a new name is proposed today, a taxonomist declares a single specimen as the element the name is to be based upon. In the jargon of taxonomists, this single sheet is termed a holotype. The rules for naming new plants in Pursh's time were less precise, and he only had to mention the collection, or collections, he used to describe his new plant. Again, in taxonomic jargon, each of the herbarium specimens is called a syntype.

In the case of Pursh's Helonias tenax, formally proposed in his book Flora americae septentrionalis in December of 1813, he saw at least two herbarium specimens, both gathered by Lewis. In 1999, as may be seen on one of the labels attached to the specimen, this sheet was selected as the one herbarium sheet to represent Pursh's concept of his Helonias tenax. This sheet is termed a lectotype, namely a type specimen selected by others to serve as the representative element.

Although devoid of its original color, fragrance and tactile qualities, this flat, brown, dried-out specimen supplies the scientist with important information that can be acquired in no other way: its morphology .the plant's form and structure apart from its function in the biotic community .and other identifying characteristics, such as DNA, which are now studied with the tools and methods of molecular biology.

The original label on a specimen sheet tells where and when the specimen was collected. Additional annotation labels provide other information such as who described and named it, where the original name and description were first published, and when and by whom new identifications, if any, were made by others.

In 1815 William Clark gave all of Lewis's botanical specimens to the American Philosophical Society in Philadelphia, except some that Frederick Pursh had already taken back to Europe with him. There they lay in bundles, unremembered and unnoticed, until 1896, when botanist Thomas Meehan found them and secured permission to take them back to his institution, The Academy of Natural Sciences, to study and catalog them, and prepare them for proper storage. Some forty years later the specimens and the labels accumulated up to that time were transferred to new specimen sheets. They are still on deposit, or long-term loan, at the Academy—identified on this sheet by the perforated letters ANS PHILA. As custodian of the herbarium, it is the Academy's responsibility to maintain and continue the collection's provenance, or record of origin and identification.

Lewis brought back his specimens in folded sheets of blotter paper such as he had used to dry them. In the 1920s A. E. Fogg, an intern at the Academy, attached all 222 of the Lewis and Clark specimens now on deposit there to standard sheets such as the one above, measuring 11½" by 16¾".


Funded in part by a grant from the Montana Committee for the Humanities