Pediomelum hypogaeum

Pediomelum hypogaeum (also known as Psoralea hypogaea) is a perennial herb also known as the Little Indian Breadroot. It is found on the black soil prairies in Texas. It has an infloresence on stems 5-6 centimeters long, separate from the leaves, arising from a subterranean stem and deep carrot-shaped root that is 3-7 cm long. The long petioled leaves are palmately divided into 5 linear-elliptic leaflets that are 3-5 centimeters long. The flowers, borne in condensed spikes separate from the leaves, are purple and pea-like, and have surprisingly strong scent, reminiscent of lemon furniture polish. The species has edible tuberous roots.

Reference

 * Delena Tull (1987), Edible and Useful Pants of Texas and the Southwest, pgs 86-87