This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Erect or ascending, stout, branched, finely appressed-pubescent, at least above, 1°-2° high, from a long deep tuberous-thickened root. Petioles equalling or shorter than the leaves, 1 1/2'-2' long; stipules linear, acuminate, 6"-8" long; leaflets 5, digitate, short-stalked, entire, broadly oblanceolate or oval, obtuse and commonly mucronate at the apex, narrowed or cuneate at the base, 1'-2' long, 4"-7" wide; spikes oblong, dense, 1 1/2'-3' long, 1'-1 1/2' thick; peduncles longer than the petioles; bracts lanceolate, long-cuspidate, equalling or exceeding the bluish corolla; pod oval, membranous, enclosed in the calyx.
Psoralea esculenta Pursh, Fl. Am. Sept. 475. 1814.
Rather stout, erect from a large farinaceous root or cluster or roots, little branched, 4'-18' high, densely villous-pubescent with whitish hairs. Lower petioles 2-4 times longer than the leaves; stipules lanceolate, 8"-12" long; leaflets 5, digitate, short-stalked, oval or obovate, entire, obtuse, narrowed at base, 1'-2' long, 4"-10" wide; peduncles equalling or longer than the petioles; spikes oblong, dense, 1 1/2'-3' long, 1'-1 1/2' thick; bracts lanceolate or ovate, acute, 5"-8" long, nearly equalling the bluish corolla; pod oblong, glabrous, about 2 1/2" long, slightly wrinkled, enclosed in the calyx-tube.
Prairies and plains, Manitoba and North Dakota to Wisconsin, Montana, Missouri, Nebraska and Texas. Missouri bread-root. Cree- or prairie-potato. Tipsin. Tipsinna. June.
Psoralea hypogeae Nutt; T. & G. Fl. N. A. 1: 302. 1838.
Similar to the preceding species, but smaller, nearly acaulescent, the stem hardly rising above the ground, densely pubescent with appressed whitish hairs. Petioles 2-4 times as long as the leaves; stipules oblong, acutish, about 6" long; leaflets 5, digitate, sessile or nearly so, linear-oblong or oblanceolate, 1'-1 1/2' long, 2"-3" wide, entire, often mucronate-tipped, narrowed at the base; peduncles Ľ-3' long; spikes short, dense, 1/2'-1' long; bracts ovate, acute, shorter than or nearly equalling the dull blue corolla; pod 5" long or more, somewhat hirsute, slender-beaked.
Plains, Nebraska and Colorado to Texas, Montana and New Mexico. May-June.
Psoralea stipulata T. & G. Fl. N. A. 1: 688. 1840.
Sparingly pubescent or glabrous, nearly glandless, branched, diffuse or ascending, stems 1°-2° long. Petioles shorter than the leaves; stipules foliaceous, ovate or lanceolate, about 6" long; leaves pinnately 3-folio-late; leaflets oval or elliptic, l'-2' long, entire, narrowed at the base, obtusish at the apex, the terminal one on a stalk 3"-6" long; peduncles mainly axillary, longer than the petioles; racemes short, dense, l' long or less; flowers purple, 4"-5" long; bracts ovate, acute or acuminate, membranous, deciduous; pod not seen.
In rocky places, Ohio, Indiana and Kentucky. Local. June-July.