The purpose of this book is to identify and describe the Great Plains animals and plants that were encountered and described by Lewis and Clark and their Corps of Discovery two centuries ago during their famous exploratory expedition of the Louisiana Purchase territories. It also attempts to place both the organisms they discovered in an ecological framework and these two explorers in a historical context as biologists. It is intended to serve as a bicentennial tribute to this remarkable exploration of the then-unknown lands comprising the Louisiana Purchase. The bicentennial of this epic journey seems an especially appropriate time to review and marvel at the expedition's accomplishments, and to reflect on the changes in the land and its associated biota that have occurred during the subsequent two hundred years of American history.
The animals selected for inclusion in this survey represent as many as possible of the identifiable species of vertebrates that were initially described, or at least apparently discovered, by the Lewis and Clark expedition while crossing the Great Plains as well as those previously known species that were described in sufficient detail to permit identification with some degree of confidence. Special attention has been given to those animal species encountered by the Corps of Discovery that were previously unknown, or ones for which important new biological information was obtained during the expedition. However, a few distinctly western and montane-adapted animals such as the blue grouse (Dendragapus obscurus) and pinyon jay (Gymnorhinus cyanocephalus) were excluded. Both of these forest-adapted birds were encountered at the very edge of the Great Plains in western Montana. A few additional western or northern species, such as the Columbian ground squirrel, lynx, and moose, were likewise deemed to be of doubtful species identification or of questionable geographic affinities. These species have been included in the survey, but their names are set off by parentheses.
The plants chosen for inclusion in the text represent all those species collected on the Great Plains and preserved as herbarium specimens that are known to be still extant. Selecting the western limits of the Great Plains in order to decide which plant species to include was a subjective exercise, but those species whose ranges fall largely or entirely outside the coverage of the Atlas of the Flora of the Great Plains were excluded. These include antelope bush (Purshia tridentata), golden currant (Ribes aureum), moundscale (Atriplex gardneri), and common monkey-flower (Mimulus guttatus). The comments made in the text as to Native American ritual or medicinal uses of plants derive mostly from Gilmore (1977) and Kindscher (1992); the latter reference is especially valuable as to plant medicinal properties.
This summary of the animals and plants encountered by Lewis and Clark is organized in three parts, corresponding to three broad and roughly equal geographic regions, at least in terms of river distances traveled. Accompanying the summary are maps of the major campsites and associated dates spent by the Corps of Discovery in each of these three regions. The Corps spent much more time exploring during the upstream, outward-bound phase in 1804 and 1805 than during the return journey, and this first part of the expedition was by far the richest from a biological standpoint. Almost no new species were discovered during the return trip in 1806, and the associated campsites are not mapped.
In general, the animals and plants that the expedition encountered are described only for that phase of the expedition where they were first encountered. However, a few especially important mammals (e.g., bison, pronghorn, elk, wolf, and grizzly bear) are discussed in two or all three of the geographic regions recognized here. Names of present-day states or counties as well as current town locations have often been used to provide convenient geographic reference points for the reader. Included are drawings of all the certainly discovered or initially well- described vertebrates, as well as some representative plants, especially species of genera having special ritual or medicinal value for Native Americans, such as Artemisia, Juniperus, and Nicotiana. The names used in the text for Native American tribes are modern ones, although alternate names used by Lewis and Clark are typically shown parenthetically.
When this book had nearly gone to press, H. Wayne Phillips's Plants of the Lewis and Clark Expedition (2003) appeared. He illustrated more than 80 tallgrass and high-plains species, including some that are not included here because herbarium specimens are not known to exist.