1	Plants only with long shoots, without short shoots, unarmed; leaves alternate; flowers 4- or 5-merous; petals present or absent		(2)
+	Plants with both long and short shoots, apices of short shoots often terminating in a woody spine; leaves opposite or alternate on long shoots, clustered or fascicled on short shoots; flowers unisexual and plants dioecious, 4-merous; petals present (R. sect. Rhamnus)		(16)
2 (1)	Flowers polygamous, 4-merous; petals absent; ovary 4-loculed, rarely 3-loculed; flowers usually fascicled in axils of leaves; inflorescences never with leaflike bracts (R. sect. Tetrarhamnus)		(3)
+	Flowers unisexual and plants dioecious, rarely polygamous, 5-merous; petals usually present; ovary 3-loculed; flowers solitary or few fascicled in axillary cymose racemes or cymose panicles; inflorescences with small, leaflike bracts (R. sect. Pseudoceanothus)		(5)
3 (2)	Leaf blade 2-4.5 cm, apex obtuse or rounded, margin entire, both surfaces yellow tomentulose, velutinous, lateral veins 5 or 6(-8) pairs.		8 R. ninglangensis
+	Leaf blade 5-20 cm, apex acuminate or long acuminate, margin serrate, abaxially puberulent on veins or barbate in axils of veins, lateral veins 9-17 pairs		(4)
4 (3)	Deciduous trees or shrubs; young branches puberulent; leaves papery, abaxially sparsely pubescent on veins.		7 R. sargentiana
+	Evergreen trees or shrubs; young branches glabrous; leaves leathery, abaxially glabrous or barbellate in axils of leaves.		6 R. hemsleyana
5 (2)	Flowers few, solitary or 2-6-fascicled in axils of leaves		(6)
+	Flowers numerous, in cymose racemes or cymose panicles		(9)
6 (5)	Leaf blade to 4 cm, lateral veins 2-4 pairs		(7)
+	Leaf blade usually longer than 4 cm, lateral veins 4-6 pairs		(8)
7 (6)	Leaves papery, petioles 2-7 mm; flowers solitary, unisexual and plants dioecious; petals present; pedicels 1-2 mm.		9 R. heterophylla
+	Leaves thinly leathery, petioles shorter than 2 mm; flowers polygamous; petals absent; pedicels 5-6(-10) mm.		10 R. procumbens
8 (6)	Leaves leathery, lateral and reticulate veins adaxially conspicuously impressed; seeds broad at both ends, abaxially narrowly furrowed at middle part.		11 R. bodinieri
+	Leaves papery to thickly papery, lateral veins prominent on both surfaces; seeds with base broader than middle, abaxially longitudinally furrowed in upper part.		12 R. xizangensis
9 (5)	Flowers polygamous or unisexual; inflorescences often with many persistent leaflike bracts; seeds shortly furrowed for 1/2 length		(10)
+	Flowers unisexual and plants dioecious; inflorescences without leaflike bracts or with few caducous leaflike bractlets; seeds abaxially longitudinally furrowed for 3/5 length		(11)
10 (9)	Drupe 3-4 mm in diam., base with persistent sepals and calyx tube.		13 R. formosana
+	Drupe 5-6 mm in diam., sepals caducous, base with persistent calyx tube only.		14 R. hainanensis
11 (9)	Leaves abaxially hairy or only hairy on veins and petioles; petals present		(12)
+	Leaves and petioles glabrous or leaves abaxially clustered hairy in vein axils; petals present or absent		(14)
12 (11)	Leaves thickly leathery, abaxially densely tomentulose; seeds with equally broad, longitudinal furrow for 4/5 length.		15 R. kwangsiensis
+	Leaves papery or thickly papery, abaxially puberulent or only on veins; seeds abaxially furrowed for 3/4 length or for nearly entire length		(13)
13 (12)	Leaf blade narrowly elliptic or oblanceolate-elliptic; petiole shorter than 1 cm; flowers often in short cymose racemes; pedicel and calyx puberulent; seeds abaxially with furrow extending over nearly entire length.		16 R. esquirolii
+	Leaf blade elliptic to broadly elliptic; petiole 1.2-2 cm; flowers usually in large panicles; pedicel and calyx glabrous; seeds abaxially furrowed for 3/4 length.		17 R. nigricans
14 (11)	Leaf blade usually broadly elliptic or broadly oblong; young branches and inflorescence rachises puberulent; inflorescences to 12 cm; petals present.		18 R. napalensis
+	Leaf blade elliptic or oblong-elliptic; young branches and inflorescence rachises glabrous; inflorescences shorter than 5 cm; petals absent		(15)
15 (14)	Leaf blade papery or thinly leathery, apex caudate-acuminate, abaxially pale purple when dry, petiole to 18 mm.		19 R. subapetala
+	Leaf blade leathery, apex shortly acuminate or acuminate, abaxially not drying purple, petiole to 7 mm.		20 R. coriophylla
16 (1)	Leaves opposite or subopposite, rarely alternate		(17)
+	Leaves and branches alternate, rarely subopposite		(34)
17 (16)	Leaves not longer than 3 cm, narrow, usually less than 1 cm wide, lateral veins in 2 or 3, rarely 4, pairs		(18)
+	Leaves longer than 3 cm, ca. 1.5 cm wide, lateral veins (3 or)4-7 pairs		(22)
18 (17)	Leaves subleathery, both surfaces glabrous, petioles 5-20 mm, glabrous; seeds abaxially shortly furrowed for 1/2 length, obcordate.		21 R. maximovicziana
+	Leaves papery or thickly papery, both surfaces and petioles sparsely puberulent; seeds abaxially or laterally furrowed for ca. 4/5 of length		(19)
19 (18)	Leaf blade oblong or elliptic, petiole 1-3 mm		(20)
+	Leaf blade ovate, rhombic-obovate, or rhombic-elliptic, petiole 4-15 mm		(21)
20 (19)	Branchlets dark brown; bark scabrous, longitudinally fissured; leaf blade usually elliptic, abaxially black when dry, clustered hairy at vein axils or glabrous, reticulate veins inconspicuous; seeds abaxially deeply furrowed for 4/5 length.		22 R. gilgiana
+	Branchlets silvery-gray or gray-brown, slightly glabrous; leaf blade usually oblong or ovate-elliptic, abaxially golden-yellow or yellowish when dry, reticulate veins conspicuous, both surfaces puberulent, rarely subglabrous; seeds abaxially shallowly furrowed for nearly entire length.		23 R. flavescens
21 (19)	Leaf blade papery, ovate or ovate-lanceolate, abaxially yellow when dry, veins or vein axils white puberulent; seeds abaxially with broad furrow.		24 R. bungeana
+	Leaf blade thickly papery, rhombic-obovate or rhombic-elliptic, abaxially gray-white when dry, areole of vein axils puberulent; seeds abaxially with narrow furrow.		25 R. parvifolia
22 (17)	Leaf blade ovate-cordate or ovate-orbicular, base cordate or rounded, margin densely sharply serrate; fruiting pedicel 1.3-2.3 cm; seeds abaxially furrowed for 4/5 length.		26 R. arguta
+	Leaf blade not ovate-cordate, base cuneate or subrounded, margin obtusely serrate or crenate-serrate; fruiting pedicel not longer than 1.2 cm		(23)
23 (22)	Petioles usually longer than 1-1.5 cm; seeds with short abaxial furrow restricted to 1/3 of length		(24)
+	Petioles shorter than 1 cm; seeds abaxially or laterally longitudinally furrowed for more than 1/2 length (except in R. dumetorum)		(28)
24 (23)	Branchlets hairy or glabrous; leaves abaxially often turning yellow or golden-yellow when dry, veins and vein axils golden-yellow pubescent, petioles 5-15 mm.		37 R. utilis
+	Branchlets glabrous; leaves abaxially greenish when dry, glabrous, or abaxially midvein sparsely white hairy, petioles 1.5-3 cm		(25)
25 (24)	Leaf blade glabrous, margin densely crenate, elliptic or broadly elliptic, lateral veins 3 or 4 pairs.		33 R. cathartica
+	Leaf blade and petiole subglabrous, margin sparsely obtusely serrate, or crenate, orbicular, narrowly to broadly elliptic, or oblong, lateral veins 4-6 pairs		(26)
26 (25)	Leaf blade suborbicular, ovate-rhombic, or elliptic; axillary buds small; seeds easily separated from endocarp, exposing a nearly circular, distinctly margined furrow.		34 R. diamantiaca
+	Leaf blade narrowly to broadly elliptic or oblong; axillary buds 4-8 mm; seeds exposing a short, never circular furrow		(27)
27 (26)	Branches terminating in a spine or large bud; leaf blade narrowly elliptic or narrowly oblong.		35 R. ussuriensis
+	Branches terminating in a large bud, rarely spinescent; leaf blade broadly elliptic or ovate-oblong.		36 R. davurica
28 (23)	Young branches, annual branches, both surfaces of leaves, or veins and petioles puberulent; flowers and pedicels sparsely puberulent; leaf blade obovate-orbicular, ovate-orbicular, or suborbicular.		27 R. globosa
+	Young branches, annual branches, and petioles glabrous or nearly so; flowers and pedicels glabrous; leaf blade not obovate-orbicular or suborbicular		(29)
29 (28)	Leaves adaxially glabrous, abaxially vein axils clustered hairy		(30)
+	Leaves adaxially sparsely pubescent at least on veins, abaxially areoles of veins clustered hairy or rarely glabrous		(31)
30 (29)	Leaf blade narrowly elliptic or oblanceolate-elliptic, 1-2.2 cm wide, apex caudate-acuminate or long acuminate, lateral veins (4 or)5 or 6(or 7) pairs, petiole 2-6 mm.		28 R. iteinophylla
+	Leaf blade obovate or obovate-elliptic, 2-5 cm wide, apex shortly acuminate or acute, lateral veins 3-5 pairs, petiole 7-20 mm.		29 R. leptophylla
31 (29)	Branchlets pale gray or gray-brown; bark scabrous, not nitid; seeds black, abaxially at base with short furrow.		30 R. dumetorum
+	Branchlets red-brown, purple-red, or dark brown; bark laevigate, shiny; seeds red-brown or brown, abaxially with longitudinal furrow extending over 2/3 of length		(32)
32 (31)	Leaf blade rhombic-obovate or rhombic-elliptic, both surfaces glabrous or abaxially areoles of vein axils sparsely puberulent, lateral veins 2-4 pairs.		25 R. parvifolia
+	Leaf blade elliptic, obovate-elliptic, or obovate-lanceolate, adaxially sparsely hirsutulous, abaxially glabrous or areoles of vein axils sparsely pilose, lateral veins 4 or 5 pairs		(33)
33 (32)	Leaf blade usually elliptic or obovate-elliptic, abaxially yellowish or gray when dry, reticulate veins inconspicuous, vein axils often with areole, papery to thickly papery; young branches glabrous.		31 R. tangutica
+	Leaf blade usually obovate-lanceolate, abaxially often reddish when dry, reticulate veins conspicuous, vein axils without areoles, rarely with areoles, thinly papery or papery; young branches slightly pubescent or glabrous.		32 R. virgata
34 (16)	Leaves usually shorter than 1.2 cm, narrow; seeds abaxially or laterally with over 2/3 entire length longitudinal furrow		(35)
+	Leaves usually more than 3 × 2 cm; seeds abaxially or laterally with long or short furrow		(42)
35 (34)	Leaf blade linear, oblanceolate, or narrowly oblanceolate, both surfaces glabrous; seeds abaxially with narrow furrow for 4/5 entire length		(36)
+	Leaf blade elliptic, obovate-elliptic, or spatulate, both surfaces puberulent, or abaxially puberulent on veins, rarely glabrous; seeds with broad or narrow furrow		(37)
36 (35)	Leaf blade narrowly lanceolate to narrowly obovate, 3-5 cm, apex acute or obtuse, petiole 3-15 mm; branches terminating in a spine; erect shrubs or small trees.		38 R. erythroxylum
+	Leaf blade oblanceolate or narrowly oblanceolate, 1-2.5 cm, apex obtuse or emarginate, petiole 2-3 mm; branches terminating in a small bud, not spinescent; procumbent small shrubs.		39 R. tzekweiensis
37 (35)	Leaves at both surfaces, or at least major veins, yellowish verrucose-pilosulose; flowers and pedicels sparsely pilose.		40 R. aurea
+	Leaves glabrous or puberulent or abaxially vein axils clustered hairy; flowers and pedicels glabrous		(38)
38 (37)	Leaves leathery or nearly so; seeds abaxially or laterally with deep furrow		(39)
+	Leaves papery; seeds abaxially with broad, shallow furrow		(40)
39 (38)	Branchlets spreading, often virgate, purple-red or dark purple, smooth, shiny; leaf blade subleathery, oblanceolate or obovate-elliptic, apex obtuse or emarginate, glabrous or subglabrous; seeds abaxially with broad furrow.		41 R. leptacantha
+	Branchlets not virgate, gray-brown or dark brown, scabrous, with longitudinally arranged slits, not shiny; leaf blade leathery, spatulate or rhombic-elliptic, apex truncate or acute, adaxially glabrous or midvein sparsely puberulent, abaxially with ± distinct bearded domatia in axils of primary and lateral veins; seeds abaxially with narrower furrow.		42 R. rosthornii
40 (38)	Leaf blade elliptic or oblong, margin entire or abaxially inconspicuously serrulate above middle, glabrous, lateral veins 3 or 4 pairs; flowers 10-20-clustered at leaf axils.		43 R. songorica
+	Leaf blade obovate or obovate-elliptic, rarely elliptic, both surfaces sparsely puberulent, margin sparsely serrulate, lateral veins 2 or 3 pairs; flowers 2-5-clustered at leaf axils or terminal on short shoots		(41)
41 (40)	Leaves 5-10 mm, obovate; profusely shortly branched, pulvinate compact shrubs, 10-25 cm tall.		44 R. minuta
+	Leaves ca. 2.2 mm, elliptic or ovate-elliptic; prostrate, small shrubs, to 200 cm tall.		45 R. prostrata
42 (34)	Young branches, leaves, petioles, flowers, and pedicels glabrous		(43)
+	Young branches, both surfaces of leaves, leaf veins, or vein axils hairy; flowers and pedicels puberulent or glabrous		(46)
43 (42)	Leaf blade membranous, oblong-ovate or ovate-orbicular, margin crenate to serrate; terminal bud not spinescent.		46 R. nakaharae
+	Leaf blade papery, elliptic, oblong-elliptic, or broadly elliptic, margin hooklike crenate; terminal bud spinescent		(44)
44 (43)	Leaf blade apically shortly acuminate, petiole 1-1.5 cm; seeds abaxially with margined furrow for 5/7 of length.		49 R. hupehensis
+	Leaf blade apically caudate-acuminate or long acuminate, petiole not longer than 1 cm; seeds with margined furrow for 1/2 of length		(45)
45 (44)	Petioles 2-4 mm; seeds abaxially with margined furrow for 2/5-1/2 of length, apex without fissured line.		47 R. wilsonii
+	Petioles 5-10 mm; seeds abaxially with margined furrow for 1/4-1/3 of length, apex with fissured line.		48 R. lamprophylla
46 (42)	Calyx and pedicel sparsely puberulent; annual branches, both leaf surfaces, or at least leaf veins pubescent		(47)
+	Calyx and pedicel glabrous; leaves subglabrous or ± hairy		(49)
47 (46)	Leaf blade thickly papery, obovate-elliptic or obovate-orbicular, adaxially veins conspicuously impressed, distinctly rugose when dry; seeds abaxially with margined furrow nearly as long as entire length, above furrow without fissured line.		50 R. rugulosa
+	Leaf blade papery or thinly papery, veins adaxially not rugose when dry; seeds abaxially with fissured furrow for 1/4-2/5 of length, above furrow with fissured line		(48)
48 (47)	Leaf blade broadly elliptic, obovate-elliptic, or ovate-orbicular, apex shortly acuminate or acuminate, petiole 7-25 mm; fruiting pedicel 7-14 mm.		51 R. koraiensis
+	Leaf blade oblanceolate-oblong or elliptic, apex long acuminate or caudate-acuminate, petiole 3-8 mm; fruiting pedicel 4-7 mm.		52 R. grandiflora
49 (46)	Leaf blade membranous, ovate or elliptic-ovate, glabrous, or midvein adaxially and veins abaxially sparsely pilose.		53 R. liukiuensis
+	Leaf blade papery; seeds abaxially with, long or short furrow		(50)
50 (49)	Seeds abaxially with margined furrow for nearly entire length; leaves abaxially sparsely clustered hairy in vein axils		(51)
+	Seeds abaxially with margined furrow for 1/3-1/2 of length; leaves adaxially glabrous, or pubescent on veins		(52)
51 (50)	Leaf blade oblong or ovate-oblong.		54 R. wumingensis
+	Leaf blade ovate-elliptic, obovate-elliptic, or obovate.		50 R. rugulosa
52 (50)	Seeds abaxially with margined furrow for nearly 1/2 of length, above furrow without fissured line		(53)
+	Seeds abaxially with basal rim shortly furrowed for less than 1/3 of length, above furrow with fissured line		(54)
53 (52)	Leaf blade usually broadly elliptic, abaxially pubescent especially on veins, petiole 2-4 mm.		47 R. wilsonii
+	Leaf blade oblong or ovate-oblong, abaxially often turning reddish when dry, glabrous, petiole 4-9 mm.		55 R. brachypoda
54 (52)	Branchlets gray-brown, not shiny, terminating in an obtuse spine; leaves often reflexed when dry, adaxially glabrous, abaxially veins or veins axils pilose, petioles 3-6 mm, glabrous or puberulent.		56 R. fulvotincta
+	Branchlets yellow-brown, shiny, terminating in a sharp spine; leaves not reflexed when dry, adaxially white adpressed hairy or pilose, abaxially veins or vein axils pilose or glabrous, petioles 6-25 mm, sparsely or densely pubescent.		57 R. schneideri