Herbs, annual, 1–8 dm, sparsely to densely pubescent. Cotyle­dons persistent or deciduous (leaving circular scar), disclike, sessile. Stems ascending or erect, branched near base or middle, or unbranched, hollow, at least near base. Leaves cau­line; petiole 3–15 cm; leaflets 5–9(–11), blades 10–50 × 2–12 mm, adaxial surface glabrous. Peduncles 2–30 cm; bracts persistent, reflexed, 3.5–12 mm. Racemes 4–60 cm; flowers in crowded to widely spaced whorls. Pedicels 0.5–5 mm. Flowers 8–18 mm; calyx appendages usually absent, sometimes present, abaxial lobe 5–11 mm, adaxial lobe 2–6 mm; corolla white to dark yellow, pink to dark rose, or lavender to purple, lower wing margins sometimes ciliate, upper margins usually ciliate near claw, upper keel margins usually ciliate near claw, lower margins sometimes ciliate but not as densely. Legumes 1–1.8 cm, pubescent. Seeds 2, tan to brown, usually mottled, ridged or smooth.

Distribution

w North America, nw Mexico, South America.

Discussion

Varieties 3 (3 in the flora).

Lupinus microcarpus is highly variable and with varieties intergrading.

Selected References

None.

Lower Taxa

Lupinus microcarpus var. densiflorus, Lupinus microcarpus var. horizontalis, Lupinus microcarpus var. microcarpus

Key

1	Wings broadly elliptic, persistent and becoming translucent, upper and usually lower margins ciliate near claw; lower keel margins ciliate near claw; calyx appendages 1–2 mm.	Lupinus microcarpus var. horizontalis
1	Wings linear to oblanceolate, withering, not becoming translucent, upper margins usually ciliate near claw, lower rarely; lower keel margins sometimes ciliate near claw or sparsely so; calyx appendages usually absent.	> 2
2	Calyx and flower bracts with long shaggy hairs; legumes usually erect or spreading.	Lupinus microcarpus var. microcarpus
2	Calyx and flower bracts with few short and appressed, or long and spreading hairs; legumes usually secund, sometimes spreading.	Lupinus microcarpus var. densiflorus