The radicles are numerous, rather large, white, flexible, succulent and diverging.
The bulb is white when raw. It turns black when baked.
Rendering by Bob Gilman
The term "radicles" here refers to the roots at the base of the bulb. The entire structure—roots and bulbs—is a "radi"X and in this case a specialized type—a tunicate bulb (e.g., having scales). Lewis's use of "radicale" in his description means the leaves arise from the top of the bulb. The term is correctly spelled "radical."
In other words:2
radical—"Pertaining to the root; radical leaves are basal leaves, which seem to arise from the root crown."
tunicate—"Covered or provided with sheathing leaf bases which form concentric circles when viewed in cross section, as the bulb of an onion."
succulent—"Fleshy and juicy; more specifically, a plant which accumulates reserves of water in the fleshy stems or leaves, due largely to the high proportion of hydrophilic colloids in the protoplasm and cell sap."
diverge—To extend in different directions from a common point.
1. Lewis had crossed out this bracketed word, as indicated in Gary Moulton's edition of the journals.
2. Definitions in quotes are from the glossary to Intermountain Flora: Vascular Plants of the Intermountain West, U.S.A., by Arthur Cronquist, Arthur H. Holmgren, Noel H. Holmgren, and James L. Reveal (6 vols., 1972; reprint, New York: The New York Botanical Garden, 1986), 1:249-66. Definitions not enclosed in quotes are from The American Heritage Dictionary of the English Language (4th ed., Boston: Houghton Mifflin Company, 2000).
Supported in part by a grant from the Idaho Governor's Lewis and Clark Trail Committee