Bitterbrush (Purshia tridentata (Pursh) DC.)
Collected on "the prarie of the knobs," Nevada Valley,
Powell Co., Montana, 6 Jul 1806
Photo © 2000 James L. Reveal
Now in Canada, with little in the way of a livelihood, Pursh did some minor collecting, but expressed hopes of doing a flora of Canada. By 1818, with some minor support, he collected in the Gulf of St. Lawrence only to have his entire collection burn in a house fire in Montreal the following year. The year 1818 also marked the publication of Nuttall's Genera of North American plants, which forever limited the sale of Pursh's Flora. Drinking still and in poor health, Pursh died destitute in Montreal on July 11, 1820.
One cannot leave Pursh without commenting on his brief success. While his Flora had many flaws, they were no more serious than those found in any other work treating a large portion of the world's flora. He has been criticized for his means of acquiring new and interesting plants and for ignoring the contributions of others, yet he was remarkably thorough for his time. He modified the Linnaean system of arranging plants into groups, making his groupings of plants much more natural than anything published to that time. He was careful to indicate whose specimens he saw and where he saw them, and where the plants grew in the wild. He annotated specimens so that today it is possible to find his comments on the herbarium sheets he examined in London and Oxford.
Pursh was a good collector, taking full and complete specimens so that one can readily identify his material today. While socially he was probably a misfit in both Philadelphia and London, he was nonetheless a gifted observer and a careful judge of what a species should be. He did what he had to do with the Lewis and Clark collection. We now know that he did not "steal" the specimens, for Muhlenberg knew he had them in his possession. Also, it must be said that the Lewis and Clark collection was not well cared for by the American Philosophical Society, whereas the specimens that Pursh retained and gave to Lambert were properly curated.
It is perhaps fitting that the western shrub that bears Pursh's name, Purshia (per-SHE-ah), should be called bitterbrush. It is a remarkably hardy shrub wherever it occurs, and ranges widely from the deserts to the higher mountain ridges. Seemingly an awkward and often misplaced plant in the field, it is nonetheless a major food plant for grazing animals, especially deer and antelope. It may be bitter for humans to taste, but it serves its function well as Pursh served his.
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