It is unclear whether this passage may be describing digging for roots of Helianthus tuberosus or for Amphicarpaea bracteata.
Capt. Lewis, April, 9 1805--when we halted for dinner the squaw busied herself in serching for the wild artichokes which the mice collect and deposit in large hoards. this operation she performed by penetrating the earth with a sharp stick about some small collections of drift wood. her labour soon proved successful, and she procured a good quantity of these roots. the flavor of this root resembles that of the Jerusalem Artichoke, and the stalk of the weed which produces it is also similar, tho' both the root and stalk are much smaller than the Jarusalem Artichoke. the root is white and of an ovate form, from one to three inches in length and usually about the size of a man's finger. one stalk produces from two to four , and somitimes six of these roots.
Capt. Lewis, July 17, 1805--The sunflower is in bloom and (Copy for Dr Barton) and abundant in the river bottoms. The Indians of the Missouri particularly those who do not cultivate maze make great uce of the seed of this plant for bread, or use it in thickening their soope. they most commonly first parch the seed and then pound them between two smooth stones untill they reduce it to a fine meal. to this they sometimes mearly add a portion of water and drink in that state, or add a sufficient quantity of marrow grease to reduce it to the consistency of common dough and eate it in that manner. the last composition I think much best and have eat it in that state heartily and think it a pallateable dish.
Capt. Lewis, August 22, 1805--a third speceis were about the size of a nutmeg, and of an irregularly rounded form, something like the smallest of the Jarusalem artichoke, which they also resemble in every other appearance. they had become very hard by being dryed. these I also boiled agreeably to the instruction of the Indians and found them very agreeable. they resemble the Jerusalem Artichoke very much in their flavor and I thought them preferable, however there is some allowance to be made for the length of time I have now been without vegitable food to which I was always much attatched. these are certainly the best root[s] I have yet seen in uce among the Indians. I asked the Indians to shew me the plant of which these roots formed a part but they informed me that neither of them grew near this place.