Shrubs, rarely perennial herbs, (0.3–)0.5–0.8(–1.2) m; usually rhizomatous. Stems finely stri­ate longitudinally, sparsely gland-dotted or eglandular, usu­ally canescent becoming gla­brate, rarely glabrous. Leaves (3–)6–12(–15) cm; stip­ules lin­ear to linear-lanceolate or seta­ceous, (1.2–)2–3(–3.5) mm, eglan­dular, canescent abax­ially, glabrous adaxially; petiole 0.5–3(–5) mm, eglandular, tomentose to canescent; rachis eglandular, tomentose to canescent or puberulent; leaflets (11–)27–41(–49), stipels acicular, (0.5–)0.8–1.2 mm, petiolule 0.5–1(–1.8) mm, usually eglandular, usually canescent to pilose, blade usually elliptic to oblong or ovate, rarely ovate to suborbiculate, (3–)10–18(–25) × (2–)4–7(–12) mm, base truncate or round to subcordate, margins sometimes slightly revolute, entire, apex round to obtuse or emarginate, surfaces usually canescent to velutinous, rarely glabrous; midvein terminated by a slender mucro, (0.2–)0.4–0.8(–1.2) mm. Racemes (1–)5–20(–30+)-branched, (2–)7–15(–25) cm; rachis sparsely gland-dotted, sparsely pilose to pubescent; bracteoles linear to narrowly lanceolate, (2.5–)3–4(–4.5) mm, eglandular, pilose abaxially, glabrous adaxially. Pedicels (0.4–)0.5–1.2(–1.5) mm, eglandular, sparsely pilose to pubescent. Flowers: calyx tube turbinate to somewhat campanulate, (1.5–)1.8–2(–2.5) mm, inconspicuously gland-dotted, usually densely pubescent, rarely glabrous or glabrate; lobes triangular to narrowly lanceolate, (0.6–)1–1.5(–1.8) mm; banner bright violet, broadly obcordate, 4.5–6 × 2.5–4 mm, distinctly clawed, margins entire or finely erose; fila­ments 6–8 mm, connate basally 1.5–2 mm; anthers yel­lowish to golden brown; ovary densely pilose. Legumes stipitate, (3–)3.5–4.5(–5) × 2–3.5 mm, margins curved outward abaxially, straight adaxially, at least distal 1/2–2/3 gland-dotted, usually villous, rarely glabrous. Seeds olive brown, 2–2.8 × 1–1.4 mm, smooth. 2n = 20.

Phenology: Flowering May–Aug(–Sep).
Habitat: Prairies, hillsides, open woodlands, sometimes in fields, along roadsides, mainly on the Great Plains.
Elevation: 200–1800 m.

Distribution

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Man., Ont., Ark., Colo., Ill., Ind., Iowa, Kans., La., Mich., Minn., Mo., Mont., Nebr., N.Mex., N.Dak., Okla., S.Dak., Tex., Wis., Wyo.

Discussion

The common name of Amorpha canescens stems from a historical, misguided belief that its occurrence indicated the presence of lead. It is a palatable range plant and thus subject to intensive grazing pressure; in some mowed fields, meadows, and pastures, the plant often appears as an herbaceous perennial. The Bureau of Land Management considers A. canescens to be a sensitive species in Montana, where it is presumed to be extirpated. Hybrids between A. canescens and A. fruticosa, named A. × notha E. J. Palmer, are rare. Amorpha canescens is a species of concern in Arkansas, where it is at the edge of its range; it is not rare, in general, being one of the most often cultivated species of Amorpha.

Selected References

None.

Lower Taxa

None.