1	Anthers unequal in size, 5 larger and 5 smaller		(2)
+	Anthers equal or nearly equal in size		(5)
2 (1)	Terminal and lateral leaflets equal in shape or nearly so, apex rounded or subtruncate, with short awn, lateral veins straight		(3)
+	Terminal and lateral leaflets unequal in shape, apex rounded and mucronate, lateral veins slightly curved or arched		(4)
3 (2)	Leaflets obovate, base broadly cuneate or obtuse; wings subspatulate, like keel auriculate on one side.		7 S. varians
+	Leaflets narrowly obovate or oblanceolate, base narrowly cuneate; wings oblong, base biauriculate; keel with an obtuse auricle.		8 S. biauritus
4 (2)	Rachis of panicles elongated, longer than branches; wings oblong, base obliquely truncate on both sides, with small rounded auricle on one side; keel base truncate and without auricle on lower side, upper side with small, rounded auricle at base; leaflets ca. 27 × 13.5 cm.		9 S. gengmaensis
+	Rachis of panicles not elongated, shorter than branches; wings obovate-oblong, like keel with long obtuse auricle on one side at base; leaflets 11-15 × 5-7.5 cm.		10 S. uniauritus
5 (1)	Terminal and lateral leaflets equal in shape or nearly so, lateral ones symmetric or nearly so; corolla purplish red		(6)
+	Terminal and lateral leaflets conspicuously unequal in shape, lateral ones asymmetric; corolla white, red, or purple before flowering, becoming white in full bloom		(7)
6 (5)	Leaflets 5-9.5 × 2-4 cm, sparsely puberulent abaxially; petiolules strigose; wings obovate-oblong, base with an acute auricle on one side; keel shorter than wings, falcate-oblong, base truncate, without auricle.		1 S. sinensis
+	Leaflets 7.5-13 × 3-6 cm, glabrous on both surfaces or ± puberulent abaxially; petiolules glabrous or slightly puberulent; wings and keel oblong, subequal in length, base with rounded auricles on both sides.		2 S. harmandii
7 (5)	Calyx teeth rounded or slightly obtuse at apex, to 1 mm, 2-3 × shorter than calyx tube; leaflets often with tufts of hairs in axils of veins abaxially.		3 S. suberectus
+	Calyx teeth acute or long acuminate at apex, 2-2.7 mm, as long as or slightly shorter than calyx tube; leaflets not with tufts of hairs abaxially		(8)
8 (7)	Calyx teeth lanceolate, as long as calyx tube; corolla white; standard 2-lobed at apex.		6 S. pulcher
+	Calyx teeth triangular, slightly shorter than calyx tube; corolla red or purple before flowering, becoming pinkish white or white in full bloom; standard emarginate at apex		(9)
9 (8)	Lateral veins of leaflets usually not branched, tertiary veinlets often transverse; corolla red before flowering, becoming pinkish white or white in full bloom; standard ovate-triangular; keel shorter than standard and wings.		4 S. parviflorus
+	Lateral veins of leaflets usually branched, tertiary veinlets forming a network; corolla purple before flowering, becoming white in full bloom; standard suborbicular; keel longer than standard and wings or as long as wings.		5 S. discolor