Herbs perennial, from rhizome, usually glabrous, rarely pubes­cent. Stems angled, climbing, basally branched 0–3 times, 5–15 dm. Leaves 9–12 cm; ten­drils well developed; stipules lanceolate, 15–25 × 4–10 mm, sometimes equal to distal leaf­lets; leaflets 6–12, scattered, blades ovate to lanceolate, 25–50 × 10–20 mm, surfaces glabrous or pubescent. Inflorescences 9–15-flowered, 6–10 cm. Flowers 11–13 mm; calyx lobes unequal, lateral lobes deltate to lanceolate, shorter than tube; corolla orange to yellow-cream, banner erect, blade shorter than claw, wings equal to keel; ovary glabrous. Legumes 40–70 × 4–6 mm.

Distribution

w United States.

Discussion

Varieties 2 (2 in the flora).

Selected References

None.

Lower Taxa

Lathyrus sulphureus var. argillaceus, Lathyrus sulphureus var. sulphureus

Key

1	Herbs glabrous.	Lathyrus sulphureus var. sulphureus
1	Herbs densely villous.	Lathyrus sulphureus var. argillaceus