Lewis, Clark and Pursh

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Rocky Mountain Douglas-fir (Pseudotsuga menzesii var. glauca (Beiss.) Franco)

Observed by Lewis and Clark on numerous occasions in 1805 and 1806

Medium-sized pine tree

© 2000 by James L. Reveal

picture of Lewis's journal with a drawing of a douglas-fir bract
Courtesy American Philosophical Society

Meriwether Lewis and William Clark were the next to observe the plant, Lewis describing it in detail on two occasions, and probably collecting specimens. He described the tree now called Douglas-fir while at Fort Clatsop on February 5, 1806, designating it "Fir No. 5." On February 9 he added some details and drew a figure in his journal of the distinctive bract of the cone (compare with the illustration of a Douglas-fir cone in "Rafinesque and Douglas"). On their return trip across the northern Rocky Mountains of Idaho and Montana, the captains repeatedly encountered the inland expression of the species, the Rocky Mountain Douglas-fir. It is possible that Lewis collected specimens of this tree also.

The Saxon botanist Frederick Pursh, who described many of the new Lewis and Clark species in 1813, associated the Lewis collection with Lambert's Pinus taxifolia, noting that he had two expressions. He wrote:

This elegant and tall tree has some resemblance to the following one [Pinus canadensis (can-a-DEN-sis—from Canada), now Tsuga canadensis (TSOO-gah), eastern hemlock], but the leaves are more than twice the length. I have among my specimens two varieties, or probably distinct species, which for want of fructification [cones] I cannot decide: one has acute leaves, green on both sides; the other emarginate leaves, glaucous underneath.

The "specimens" Pursh alluded to were those gathered on Vancouver Island by Menzies and whatever Lewis obtained supposedly "On the banks of the Columbia." Unfortunately, Lewis's specimens are lost, or at least not yet relocated. Given Pursh's remarks about the nature of the specimens he had at hand, it is possible the Lewis collection was the inland form with blue-green (or glaucous) needles, Pseudotsuga menziesii var. glauca (GLAW-ka, referring to the blue-green condition of the needles) or the Rocky Mountain Douglas-fir. This variant of Douglas-fir is common in Idaho and Montana. The coastal phase, or Pseudotsuga menziesii var. menziesii, only has dark yellow-green needles, and this was certainly the element Menzies found on Vancouver Island. Equally possible, of course, is that Lewis gathered Douglas-fir twice, once along the lower Columbia River (var. menziesii—his "No. 5") and again in the Rocky Mountains (var. glauca).