To gardeners, most interesting aspect of the Lewis and Clark Expedition is the great store of botanical information these pioneers brought back with them. We may never know exactly how many plants were documented, or how many specimens were collected. Myriad studies have been conducted by uncountable experts in this field and no two agree 100% on what was found.

Partly this is because Captains Lewis and Clark lost the majority of their notes and specimens taken between Fort Mandan and Great Falls in 1805 when their storage cache was flooded and all that they thought was safely preserved perished. They dug several of these pits at spots they believed to be above the flood line. They stored food, tools, gunpowder, and other items they would not need until the return trip. Though most were spared, the main cache at the mouth of the Sun River which held bear skins, medicines and the precious plant specimens was virtually destroyed. We don't know how many specimens were lost, but it is estimated at between 200 - 300.

Part of the confusion occurred when the Expedition returned. The adventures of the specimens is quite a story in itself:

• Lewis wanted to include his botanical discoveries in the journals when they were published but he did not have the training to do so.

• He gave them to his mentor, Benjamin Smith Barton of the University of Pennsylvania, who as it turned out did not have time to devote to this project.

• Barton gave the collection to Frederick Pursh, a young botanist of good credentials who was working in Philadelphia at the time as a gardener and plant collector for Philadelphia's and New York's largest estates. Lewis paid Pursh to prepare his specimens and create drawings of the plants.

• However, after over a year of work Pursh's labors ended with Lewis's death and Barton's inability to assist, and Pursh gave the collection to the surviving Captain, William Clark.

• Clark eventually gave them again to Barton who was not in good health and who died in 1815 without working with them at all.

• Barton left the Lewis and Clark specimens and his other collections to the American Philosophical Society where they were stored and ignored for 78 years.

• In the meantime, Pursh still had his notes (and it was later learned that he also had many of Lewis's specimens!). Pursh traveled all over and eventually settled in England where he worked for the Royal Botanic Gardens. Pursh worked with Aylmer Lambert who had a large private collection of pressed plants. With Lambert's guidance (and plant collection), Lewis's specimens and those of many other botanists, Pursh published Flora Americae Septentrionalis (Flora of North America) in 1813. This was a landmark volume, the likes of which had never been seen before, and it was what Lewis and Dr. Barton had intended to write. By allowing due credit to Lewis and Clark's botanical work, Pursh redeemed his cavalier treatment of their specimens somewhat.

• The majority of these specimens had become part of Lambert's collection, but were purchased by Edward Tuckerman after Lambert died in 1842, and Tuckerman gave them to the Academy of Natural Sciences in 1956.

• Forty years later the remaining Lewis and Clark specimens were discovered in storage at the American Philosophy Society, mounted on new specimen sheets and all the sheets are now cared for at the Academy today (except for nine which are at the Royal Botanic Gardens).

Given this convoluted history, it is easy to understand how difficult it would be to state irrevocably exactly what was actually collected by Captains Lewis and Clark.

And of course, part of the reason we've lost some of the information is simply due to the ravages of time which took it's toll on the specimens and journals.

Nonetheless, with thanks to the University of Natural Science's compilation into the Lewis and Clark Herbarium and to the years of research of many botanical scholars, we have a respectable list of plants whose discovery is now generally attributed to Captain Meriwether Lewis and Captain William Clark during the Lewis and Clark Expedition with the Corps of Discovery of 1804 - 1806.