Lupinus luteolus
Proc. Calif. Acad. Sci. 5: 38. 1873.
Herbs, annual, 3–16(–20) dm, sparsely pubescent or glabrate, appearing glaucous. Cotyledons persistent or deciduous, disclike (leaving a circular scar), sessile. Stems ascending or erect, branched near middle or unbranched. Leaves cauline; petiole 2–5 cm; leaflets 7–9, blades 10–30 × 4–9 mm, adaxial surface usually pubescent. Peduncles 4–15 cm; bracts persistent, reflexed, 5–11 mm, pubescent. Racemes 9–35 cm; flowers in crowded whorls. Pedicels 1–3 mm. Flowers 10–16 mm; calyx appendages usually absent, abaxial lobe entire, 6–10 mm, adaxial lobe entire, 3–5 mm; corolla usually pale yellow, sometimes pinkish or bright blue, lower wing margins rarely ciliate, upper margins ciliate near claw, lower and upper keel margins densely ciliate near claw. Legumes 1–1.5 cm, pubescent. Seeds 2, dark brown, tuberculate.
Phenology: Flowering spring–early summer.
Habitat: Clearings, open or disturbed areas.
Elevation: 0–1900 m.
Distribution
Calif., Oreg.
Discussion
Lupinus luteolus is known primarily from the North Coast area in California, with isolated collections from the Diablo Range and Western Transverse Ranges. It is known from Oregon in Douglas, Jackson, and Klamath counties.
Lupinus luteolus from Siskiyou County in California to the Klamath Range of southern Oregon and northern California often (in about 50% of specimens) has leaflets that are glabrous adaxially. Plants from Round Valley, Mendocino County, are unusually tall and sometimes have flowers blue at anthesis; they are sometimes recognized as L. milobakeri.
Selected References
None.