Subterranean Indian Breadroot

Pediomelum hypogaeum (Nutt.) Rydberg
Psoralen hypogaea Nutt.; T. & G. Fl. N. Am. 1: 302. 1838. Lotodes hypogaeum Kuntze, Rev. Gen. 194. 1891.
A subacaulescent perennial, with an oblong-fusiform tuberous root 1-1.5 cm. thick, 2-5 cm. long; stem above ground nearly none; leaves digitately 5-foliolate, clustered at the base; stipules membranous, ovate or lanceolate; petioles 3-10 cm. long, strigose with long appressed hairs; leaflets 2-5 cm. long, 5-7 mm. wide, linear, linear-oblanceolate, or linear-oblong, acute, glabrous or nearly so above, strigose beneath; peduncles usually short, from almost none to 3 cm. long; spikes very dense, 1-3 cm. long; bracts scarious, ovate, acute, hirsute, 5-8 mm. long; calyx hirsute-strigose; tube 4 mm. long; upper four lobes subulate or lance-subulate, 6 mm. long, the lowest one ovate-lanceolate, 8-10 mm. long; corolla about 12 mm. long, similar to that of P. esculentum; pod hirsute, the body ovoid, 5 mm. long, the beak flat, about 8 mm. long; seed light-brown, wrinkled.
Type locality: Plains of the Platte [Nebraska].
Distribution: Nebraska to Montana. Utah, New Mexico, and Oklahoma.