Herbs, perennial, (3–)4–8(–10) dm, hairs stiff to silky-appressed, whitish, grayish, or brownish. Cotyledons deciduous, petio­late. Stems erect, densely tufted, unbranched distally. Leaves bas­al and cauline, persisting until after flowering; stipules 4–8 mm; proximal petioles 4–20 cm, distal ones 1.5–5 cm; leaflets 6–15, blades white to greenish, (20–)25–70 × 4–10 mm, abaxial surface hairy-strigulose or sericeous, adaxial surface strigulose-silky to sparsely hairy or glabrous. Peduncles 2.5–6 cm; bracts tardily deciduous, 5–9 mm. Racemes 6–20 cm; flowers whorled or spirally arranged. Pedicels (2–)4–10 mm. Flowers 8–12 mm; calyx asymmetrical but not spurred, silky, abaxial lobe entire, 4–7 mm, adaxial lobe 2-fid, 3–5 mm; corolla pale sulfur yellow, blue, or white, banner glabrous or sparsely hairy abaxially (pubescence extending above calyx as a line), upper keel margins usually ciliate most of length, sometimes gla­brous. Legumes 2–3 cm, pilose to silky. Seeds 4 or 5, pinkish brown.

Distribution

w North America.

Discussion

Varieties 2 (2 in the flora).

Selected References

None.

Lower Taxa

Lupinus sulphureus var. bingenensis, Lupinus sulphureus var. sulphureus

Key

1	Racemes (5–)12–20 cm; flowers usually sulfur yellow (ranging from white to occasionally blue); leaflet blade adaxial surface strigose-silky to sparsely hairy or glabrous, abaxial surface hairy strigulose.	Lupinus sulphureus var. sulphureus
1	Racemes 7–10(–11) cm; flowers blue to white; leaflet blade surfaces ± equally strigulose or sericeous.	Lupinus sulphureus var. bingenensis