Plants 60-90 cm tall. Stems up to 7 mm thick, glabrous or with some subappressed to spreading hairs 0.8-1.5 mm. Leaves 6-8 cm, subsessile; stipules 4-11 mm, often reflexed, ciliate; rachis sparsely hairy like stem; leaflets in 8-11 pairs, narrowly ovate to narrowly elliptic, 10-15 × 4-6 mm, abaxially loosely and adaxially sparsely covered with appressed to subappressed hairs 0.3-1 mm, apex rounded to obtuse. Racemes 3-6 cm, rather densely (10-)15-25-flowered; peduncle 6-15 cm; bracts greenish, narrowly triangular, 3-5 mm, white ciliate. Calyx campanulate, 4-6 mm, loosely, in upper margins and teeth densely, covered with appressed to subappressed predominantly black hairs 0.2-0.3 mm; teeth unequal, triangular, 0.3-1 mm. Petals dark purplish to blackish violet; standard obovate, ca. 13 × 7 mm; wings ca. 12 mm; keel 11-11.5 mm. Legumes with a stipe 3-5.5 mm, ± spreading, obliquely ellipsoid, 3-3.5 cm, ca. 10 mm high and ca. 4 mm wide, obtusely keeled ventrally, narrowly rounded dorsally, with a beak 1-1.5 mm; valves membranous, with very short, appressed, black or white hairs 0.05-0.08 mm.
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