Psoralea rydbergii Cory

Pediomelum humile Rydberg, sp. nov
Psoralea esculenia A. Gray, PI. Wright. 2: 37 (erroneously referred). 1853.
A subacaulescent perennial, with a fusiform deep-seated root 4-6 cm. long, 1-3 cm. thick; stem above ground almost none; leaves 3-foliolate with stalked terminal leaflet, clustered at the base; stipules membranous, lanceolate; petioles 3-6 cm. long, strigose; leaflets about 2 cm. long, conspicuously glandular-punctate, strigose beneath and on the veins above, the lateral ones broadly and obliquely ovate, sessile, the terminal one broadly rounded-rhombic or suborbicular, on a rachis about 1 cm. long; peduncles about 4 cm. long, strigose; spikes dense, many-flowered, 2-3 cm. long; calyx strigose; tube about 5 mm. long; lobes linear-subulate, 7-8 mm. long; corolla purplish, 15 mm. long or more; fruit unknown.
Type collected in the valley of Rio Grande near Piedras Nigras, Coahuila, April 19, 1910, Pringle 9205 (U. S. Nat. Herb. no. 381823).
Distribution: Type locality and San Felipe, Texas.