1	Lower part of inflorescence axis articulate, nodes with bracts; seeds semiglobose, abaxial surface smooth and adaxial surface flat, with a membrane enclosing ventral hole (C. subg. Cayratia)		(2)
+	Lower part of inflorescence axis not articulate and without bracts; seeds obovoid-elliptic or triangular-obovate, ventral mid-raphe raised (C. subg. Discypharia)		(6)
2 (1)	Leaves pedate, with 5-7 leaflets		(3)
+	Leaves 3-foliolate		(4)
3 (2)	Leaflets adaxially with appressed hairs, abaxially sparsely pilose.		4 C. pedata
+	Leaflets nearly glabrous, abaxially veins sparsely pilose.		5 C. menglaensis
4 (2)	Branchlets 1-3 mm in diam.; leaves nearly membranous when dry, sparsely hispidulous, midvein sparsely pilose, petiole 2-3 cm.		3 C. lanceolata
+	Branchlets 4-5 mm in diam.; leaves papery, abaxially densely gray pubescent, petiole 8-18 cm		(5)
5 (4)	Lateral leaflets oblong or oblong-lanceolate, base of central leaflet cuneate, margin with conspicuous, fine teeth.		1 C. geniculata
+	Lateral leaflets broadly ovate or rhombic-elliptic, base of central leaflet slightly cordate, margin entire or inconspicuously toothed.		2 C. cordifolia
6 (1)	Leaves 3-foliolate		(7)
+	Leaves pedately 5-foliolate, rarely 3-foliolate		(10)
7 (6)	Tendrils racemosely 3-5-branched; leaflets oval or nearly orbicular, margin with rounded teeth, abaxially pubescent.		6 C. trifolia
+	Tendrils 2(or 3)-branched; leaflets oblong, ovate, or ovate-rhombic, margin with obtuse teeth, only abaxially sparsely pilose or glabrescent on veins		(8)
8 (7)	Leaflets 7.5-14.5 × 5.5-8 cm; tendrils trifurcate.		7 C. timoriensis
+	Leaflets 2-8 × 1.5-4 cm; tendrils bifurcate or trifurcate		(9)
9 (8)	Leaflets oblong or ovate, 4-8 × 2-4 cm; tendrils bifurcate.		10 C. japonica
+	Leaflets ovate-rhomboid, 2-5 × 1.5-2.5 cm; tendrils bifurcate or trifurcate.		9 C. maritima
10 (6)	Leaflets glabrous		(11)
+	Leaflets at least abaxially ± pubescent		(13)
11 (10)	Leaflet apically cuspidate, margin with irregular teeth, teeth slightly bent outward or forward; style and ovary forming a gradual conical structure.		8 C. medogensis
+	Leaflet apically acuminate, acute, or rounded, margin with regular teeth; style slender, conspicuously different from ovary with a sharp transition		(12)
12 (11)	Petals apically not corniculate.		10 C. japonica
+	Petals apically conspicuously corniculate.		16 C. corniculata
13 (10)	Branchlets, peduncles, petioles, and abaxial surface of leaflets brownish and with nodiferous villous hairs		(14)
+	Branchlets, peduncles, petioles, and leaves ± pubescent		(16)
14 (13)	Leaflets nearly sessile or with very short petiolules; petals apically corniculate, with ciliate margins		15 C. ciliifera
+	Petiolules conspicuous; petals apically not corniculate		(15)
15 (14)	Lateral veins of central leaflet 4-9 pairs, margin (5-)7-14(-17)-toothed on each side.		13 C. oligocarpa
+	Lateral veins of central leaflet 13-15 pairs, margin 18-22-toothed on each side.		14 C. fugongensis
16 (13)	Branchlets, petioles, and abaxial surface of leaflets densely pubescent		(17)
+	Branchlets, petioles, and leaflet veins abaxially pilose		(18)
17 (16)	Leaflets abaxially with brownish or grayish brown hairs, margin 4-11-toothed on each side.		10 C. japonica
+	Leaflets abaxially with dense grayish white hairs, margin 20-28-toothed on each side.		12 C. albifolia
18 (16)	Leaves pedate, 3-9-foliolate, leaflets or parted lobes lanceolate, obovate- oblong, or narrowly elliptic, petiole usually only 0.3-1 cm.		17 C. cardiospermoides
+	Leaves pedate, with 5 leaflets, or sometimes mixed with 3 leaflets, leaflets elliptic, elliptic-lanceolate, or ovate-elliptic, undivided, petiole usually 2-10 cm		(19)
19 (18)	Leaflets elliptic or elliptic-lanceolate, veinlets inconspicuous.		10 C. japonica
+	Leaflets ovate-lanceolate, veinlets conspicuously raised.		11 C. daliensis