Not as off-topic as it may seem!
It turns out Lewis was quite the amateur botanist, and a keen observer. Here are his descriptions of a plant he encountered during their expedition:
http://www.lewis-clark.org/content/cont ... cleID=1993
The explanations of botanical terms are written for a non-technical audience (like me!), so I found it to be a good review, and also interesting from a historical point of view.
-Robert (who can never remember the difference between a pedicel and a peduncle)
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