Description from Flora of China
Phaca salsula Pallas, Reise Russ. Reich. 3: 747. 1776; Swainsona salsula (Pallas) Taubert.
Subshrubs or perennial herbs. Stems erect or lower part stoloniferous, 0.3-0.6 m tall, rarely to 1.3 m. Branches with longitudinal rib, with sparse to dense pallid adpressed hairs. Leaves 11-21-foliolate; stipules linear-lanceolate or triangular to subulate; rachis 5-8.5 cm, adaxially grooved; petiolule short, puberulent; leaflets obovate to obovate-oblong, 5-15(-25) × 3-6(-10) mm, abaxially with appressed white fine hairs, adaxially with scattered hairs or glabrous, lateral veins inconspicuous, base rounded to broadly cuneate, apex retuse to rounded, mucronate. Racemes often longer than leaves, 6.5-13(-17) cm, 6-16-flowered; bract ovate-lanceolate. Pedicel 4-5 mm, densely white pilose, bracteoles linear to subulate. Calyx campanulate; teeth triangular, upper 2 shorter and wider, others longer and narrower, outside white pilose. Corolla red, becoming purple; standard suborbicular, reflexed outward, 12-13 × 12-16 mm, base shortly stipitate, apex retuse; wings shorter than keel, ca. 12 mm (including stalk), apex rounded, base with slightly curved stalk ca. 3 mm and auriculate lobes ca. 2 mm, lobes rounded at apex; keel ca. 13 × 4-5 mm, blunt at apex, stalk ca. 4.5 mm. Ovary ± linear, densely white pilose; style curved, only inner surface sparsely longitudinally barbate; stigma spheroidal. Legume ellipsoid or broadly ellipsoid, turgid, 1.7-3.5 × 1.7-1.8 cm, apex rounded, stalk ca. 10 mm, segments membranous, outside sparsely white pilose, densely so on suture. Seeds brown, reniform to nearly semicircular, ca. 2.5 mm; funicle 1-3 mm; hilum rounded and sunken. Fl. May-Aug, fr. Jun-Sep.
Mountain slopes, plains, wastelands, sand, oases, ditch sides, around salt ponds; 1000-3200 m. Gansu, Hebei, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shanxi, Xinjiang [Mongolia, Russia].