Herbs or shrubs, with dark glands or pellucid dots, 1-5-foliolate leaves, and purple blue pink or white flowers, mainly in spikes or racemes. Stipules broad. Calyx-lobes equal or the lower longest, or the two upper ones sometimes united. Standard ovate or orbicular, clawed; wings oblong or falcate; keel incurved, obtuse. Stamens monadelphous or diadel-phous; anthers uniform. Ovary sessile or short-stalked, 1-ovuled. Pod ovoid, short, indehiscent, 1-seeded. [Greek, scurfy, from the glandular dots, whence the name scurfy-pea.]

About 120 species, of wide geographic distribution. In addition to the following, about 25 others occur in the western United States. Type species: Psoralca bituminosa L.

Leaves digitately 3-5-foliolate (leaflets all from the same point).

Plants leafy-stemmed.

Flowers small, 2"-4" long.

Pods subglobose.

1.

P. lanceolata.

Pods ovoid, or ovate.

Pods with a short, mostly abrupt beak.

Flowers few, scattered in slender elongated racemes.

2.

P. tenuiflora.

Flowers numerous, clustered, or crowded in racemes.

3.

P. floribunda.

Pods with a slender sharp or elongated beak.

Leaflets linear; flowers in loose elongated racemes.

4.

P. linearifolia.

Leaflets linear-lanceolate, oblong, oblanceolate or obovate; flowers spiked.

Leaflets oblanceolate or obovate; pubescence gray.

5.

P. collina.

Leaflets linear-lanceolate or oblong; pubescence silvery.

Leaflets linear-lanceolate; calyx inflated in fruit.

6.

P. digitata.

Leaflets oblong; calyx not inflated in fruit.

7.

P. argophylla.

Flowers large, 6"-8" long, densely spicate.

8.

P. cuspidata.

Plants acaulescent, or nearly so, low, spreading; roots tuberous.

Leaflets oblong-cuneate.

9.

P. esculent a.

Leaflets linear-oblong.

10.

P. hypogaea.

Leaves pinnately 3-foliolate (the terminal leaflet stalked).

Racemes short, on peduncles about equalling the leaves.

11.

P. stipulata.

Racemes spicate, the peduncles elongated, much exceeding the leaves.

Leaflets oblong-lanceolate, obtuse; pods 2" long, nearly orbicular.

12.

P. pedunculata.

Leaflets ovate-lanceolate, acuminate; pods 4"-5" long, obliquely ovate.

13.

P. Onobrychis.