Description from Flora of China
Shrubs or subshrubs. Stipules lanceolate or broadly lanceolate, large, membranous or herbaceous, adnate to base of petiole. Leaves imparipinnate, 5-27-foliolate; stipels absent; leaflet blades leathery, margin entire. Raceme 4-flowered or more; bracts and bractlets rarely persistent. Calyx tubular, oblique on pedicel; teeth 5, almost equal or adaxial 2 connate. Corolla yellow, large; standard ovate or suborbicular, erect, reflexed at margins; wings obovate-oblong or subfalcate; keel incurved, equal to wings, apex blunt. Stamens diadelphous (9+1); anthers orbicular. Ovary sessile, with glandular trichomes or pubescent; style filiform; stigma small. Legume cylindric or linear, pubescent or with glandular trichomes, 1-loculed, inside pubescent or glabrous, 2-valved, with persistent calyx. Seeds subreniform, without a caruncle.
Calophaca tianschanica (B. Fedtschenko) Boissier (Trudy Bot. Inst. Akad. Nauk S.S.S.R., Ser. 1, Fl. Sist. Vyssh. Rast. 1: 137. 1933; C. nigricans var. tianschanica B. Fedtschenko, Trudy Imp. S.-Peterburgsk. Bot. Sada 24: 178. 1905) was recorded from Xinjiang by S. H. Cheng and L. K. Dai (Ill. Treatm. Princ. Pl. China (Leguminosae), 357-359. 1955). However, the present authors found no relevant specimens and therefore could not substantiate the occurrence of this species in China.
Five species: China, Russia; C Asia; three species (two endemic) in China.
(Authors: Zhu Xiangyun (朱相云); Kai Larsen)