1	Caudex leaves (at least inner ones) with a distinct leaf blade, green.		(2)
+	Caudex leaves without a distinct leaf blade, reduced, usually scalelike and not green.		(7)
2 (1)	Caudex leaves conspicuously dimorphic: outer ones scalelike and membranous, inner ones with a distinct leaf blade.		(3)
+	Caudex leaves monomorphic, all with a green leaf blade (sometimes deciduous but leaving a dark brown, persistent petiole).		(4)
3 (2)	Caudex leaves prominently basally spurred; stem leaves 3.5-4 × 1-1.3 mm		4 R. handelii
+	Caudex leaves basally spurless; stem leaves 7-14 × 1.3-2.2 mm		5 R. smithii
4 (2)	Caudex leaves sessile, without persistent, scalelike base; stem leaves with distinct basal spur		Sedum carnegiei (see above)
+	Caudex leaves distinctly petiolate, petiole to 10 mm, turning dark brown and persisting after leaf blade falls; stem leaves (when present) basally spurless.		(5)
5 (4)	Anthers dorsifixed; inflorescences helicoid-cymose		1 R. hobsonii
+	Anthers basifixed; inflorescences corymbiform, sometimes reduced to a single flower or monochasium.		(6)
6 (5)	Caudex leaf blade linear-oblanceolate to linear-rhomboid, ca. 1.5 mm wide; petals 2.5-3 mm		2 R. humilis
+	Caudex leaf blade broadly spatulate to obovate, ca. 5 mm wide; petals 5-10 mm		3 R. primuloides
7 (1)	Inflorescences dense racemes, much longer than wide, with uniformly distributed flowers		8 R. semenovii
+	Inflorescences cymose, sometimes reduced to a single flower, sometimes elongated but then clearly made up of cymes, usually in several discontinuous whorls.		(8)
8 (7)	Stem leaves 4-6, in a single whorl; plants less than 5 cm tall.		(9)
+	Stem leaves many, alternate, aggregated or subverticillate, if verticillate then plants more than 10 cm tall, less often 6-verticillate.		(10)
9 (8)	Flowers bisexual; inflorescences 13-18-flowered, bracteate, pedicels 1.5-2.5 mm; stem leaf blade 2-6 × 2.5-4 cm		6 R. prainii
+	Flowers unisexual; inflorescences 1-6-flowered, ebracteate, pedicels 10-13 mm; stem leaf blade 0.8-1.5 × 0.4-0.7 cm		7 R. stapfii
10 (8)	Old flowering stems persistent; follicles connate in basal 1/2.		(11)
+	Old flowering stems not persistent; follicles almost free.		(34)
11 (10)	Petals ca. 10 mm, margin entire or sparsely fimbriate		9 R. dumulosa
+	Petals less than 6 mm, margin entire.		(12)
12 (11)	Remnants of old shoots and stems few; flowers somewhat large.		(13)
+	Remnants of old shoots and stems numerous; flowers small.		(22)
13 (12)	Part of caudex producing new stems not enlarged each year.		(14)
+	Part of caudex producing new stems somewhat enlarged each year.		(18)
14 (13)	Caudex 0.5-0.7 cm in diam.; flowering stems 1-5, straight; flowers usually 4-merous.		(15)
+	Caudex 1-1.5 cm in diam.; flowering stems numerous, flabellate; flowers usually 5-merous, rarely 4-merous.		(16)
15 (14)	Flowering stem leaves linear		24 R. angusta
+	Flowering stem leaves lanceolate, oblong, obovate-rhombic, or broadly obovate		17 R. atuntsuensis
16 (14)	Petals often red		21 R. fastigiata
+	Petals often yellow, especially when sepals yellow or yellowish green.		(17)
17 (16)	Stem leaves linear, linear-lanceolate, or lanceolate; stamens usually shorter than petals		22 R. pamiroalaica
+	Stem leaves elliptic; stamens equaling or longer than petals		23 R. litwinowii
18 (13)	Flowering stems often straw-colored when dry; leaves smooth.		(19)
+	Flowering stems often purplish red or pink when dry; leaves finely and minutely hairy.		(20)
19 (18)	Plants pubescent		25 R. himalensis
+	Plants glabrous		28 R. tangutica
20 (18)	Stem leaf margin entire; petals greenish yellow; pedicels densely papillate		27 R. sherriffii
+	Stem leaf margin entire or apically dentate; petals deep purple; pedicels smooth.		(21)
21 (20)	Stem leaves 1.7-2.7 × 0.4-1 cm		25 R. himalensis
+	Stem leaves 0.8-1.5 × ca. 0.2 cm		26 R. alsia
22 (12)	Nectar scales linear to broadly so		10 R. gelida
+	Nectar scales suboblong, quadrangular, or suborbicular.		(23)
23 (22)	Stem leaves elliptic to ovate or ovate-lanceolate.		(24)
+	Stem leaves lanceolate to ovate or oblong-oblanceolate, rarely linear to oblong-linear.		(28)
24 (23)	Stem leaves shortly petiolate, margin irregularly crenulate		16 R. subopposita
+	Stem leaves sessile, margin entire (coarsely dentate in R. recticaulis).		(25)
25 (24)	Flowering stems less than 4 cm		17 R. atuntsuensis
+	Flowering stems more than 12 cm.		(26)
26 (25)	Petals yellow; stem leaf margin coarsely dentate; inflorescences corymbiform-capitate		18 R. recticaulis
+	Petals purplish red or red; stem leaf margin entire, sometimes mammillate; inflorescences cymose.		(27)
27 (26)	Plants (6-)15-18 cm tall; stem leaves ovate or ovate-lanceolate; flowers often 4-merous		19 R. gannanica
+	Plants to 30 cm tall; stem leaves linear to narrowly ovate; flowers usually 5-merous		20 R. tibetica
28 (23)	Caudex base not or only slightly enlarged.		(29)
+	Caudex base enlarged.		(31)
29 (28)	Stems 1-2 mm in diam.		15 R. nobilis
+	Stems 0.5-1 mm in diam.		(30)
30 (29)	Flowering stems blackening when old; caudex leaves 6-8 mm wide; sepal apex subobtuse to obtuse		12 R. coccinea
+	Flowering stems grayish when old; caudex leaves 3-5 mm wide; sepal apex acute		14 R. kashgarica
31 (28)	Caudex densely clustered; leaves linear-lanceolate		12 R. coccinea
+	Caudex slightly or not clustered; leaves linear.		(32)
32 (31)	Caudex less than 1 cm in diam., persistent old flowering stems and branches usually few; flowers often white, 5-merous; inflorescences ca. 1 cm in diam.		13 R. kansuensis
+	Caudex 1-3 cm in diam., persistent old flowering stems and branches usually more than 100; flowers often purplish red, 4-merous; inflorescences 1.2-1.5 cm in diam.		(33)
33 (32)	Winter bud at apex of rhizome conspicuous; flowering stems 6-9 cm		11 R. quadrifida
+	Winter bud at apex of rhizome absent; flowering stems 1-5 cm		12 R. coccinea
34 (10)	Flowers usually bisexual.		(35)
+	Flowers usually unisexual (plants hermaphroditic or rarely gynodioecious in R. purpureoviridis subsp. phariensis).		(44)
35 (34)	Petals apex awnlike, with a mucro to 1 mm		55 R. liciae
+	Petals apex subobtuse.		(36)
36 (35)	Flowering stems leafy at middle or near apex.		(37)
+	Flowering stems leafy throughout.		(39)
37 (36)	Flowering stems with leaves in a whorl at middle of stem		54 R. sexifolia
+	Flowering stems with leaves grouped near apex of stem.		(38)
38 (37)	Stem leaves 1-1.5 cm		52 R. chrysanthemifolia
+	Stem leaves 2-3 cm		53 R. ovatisepala
39 (36)	Stem leaves 2-4 cm, margin divided.		(40)
+	Stem leaves 1-2.3(-3) cm, margin serrate or dentate.		(41)
40 (39)	Flowering stems ca. 15 cm; stem leaves elliptic to obovate, 5-7 cm; sepals ca. 3 mm		48 R. sinuata
+	Flowering stems 8-11 cm; stem leaves oblong, 1-3 cm; sepals ca. 6 mm		49 R. tieghemii
41 (39)	Stem leaf margin with 4 or 5 dentate lobes on each side		50 R. sacra
+	Stem leaf margin with 2 to several shallowly incised serrations on each side.		(42)
42 (41)	Stem leaves 0.2-0.3 cm wide		42 R. wallichiana
+	Stem leaves 0.4-1.1 cm wide.		(43)
43 (42)	Stem leaves elliptic, narrowly ovate, or ovate, margin irregularly and remotely serrate, base shallowly cordate; petal margin entire		38 R. purpureoviridis
+	Stem leaves oblong to obovate-oblong, margin with 2 shallowly incised serrations on each side, base attenuate; petal margin apically erose		51 R. alterna
44 (34)	Carpel beak reflexed.		(45)
+	Carpel beak not reflexed.		(46)
45 (44)	Sepals 0.5-1 mm; petals spatulate to oblong-lanceolate		46 R. yunnanensis
+	Sepals ca. 3 mm; petals oblong or triangular-ovate		47 R. forrestii
46 (44)	Carpels ovoid or narrowly so, basally narrowed.		(47)
+	Carpels oblong or narrowly so, basally thickened.		(50)
47 (46)	Flowers usually bisexual		42 R. wallichiana
+	Flowers unisexual.		(48)
48 (47)	Carpels ovoid, 9-11 mm; stem leaves obtrullate to linear-lanceolate		45 R. macrocarpa
+	Carpels narrowly ovoid, 7-9 mm; stem leaves narrowly elliptic to lanceolate or oblanceolate, or widely oblanceolate.		(49)
49 (48)	Caudex 0.5-1 cm in diam.; stem leaves 0.6-0.8 cm wide; stamens equaling or slightly longer than petals		43 R. stephanii
+	Caudex 1-2 cm in diam.; stem leaves 0.3-0.5 cm wide; stamens ca. 1.5 × as long as petals		44 R. pinnatifida
50 (46)	Carpels oblong, ca. 2 × as long as wide.		(51)
+	Carpels narrowly oblong, over 3 × as long as wide.		(54)
51 (50)	Plants glandular hairy; flowering stems more than 2 per caudex apex		38 R. purpureoviridis
+	Plants not glandular hairy; flowering stems 1 or 2 per caudex apex.		(52)
52 (51)	Flowering stems transversely wrinkled, mostly leafless; caudex elongate and rhizomelike, covered by scree so that only inflorescences are visible above ground		41 R. atsaensis
+	Flowering stems smooth or longitudinally ridged, leafy; caudex often erect or almost so, not deeply buried.		(53)
53 (52)	Caudex subprostrate, ascending, or suberect; stem leaves abaxially ± glaucescent; petals of male flowers 5-6 × 1.2-2 mm, those of female flowers 3-4 × 0.9-1.2 mm		39 R. discolor
+	Caudex erect; stem leaves abaxially not glaucescent; petals of male flowers 2.8-4 × 1.2-1.6 mm, those of female flowers 1.5-3 × 0.5-0.7 mm		40 R. bupleuroides
54 (50)	Stem leaves linear to oblanceolate, margin entire or remotely dentate.		(55)
+	Stem leaves oblong, elliptic, lanceolate, rhombic-ovate, ovate-triangular, or orbicular-cordate, margin crenulate throughout, apically dentate, or sometimes subentire.		(56)
55 (54)	Caudex prostrate, 0.2-0.4 cm in diam.; flowering stems 2-12 cm; sepals 3-4.5 mm, apex obtuse		36 R. cretinii
+	Caudex erect, 1.5-2.5 cm in diam.; flowering stems 15-60 cm; sepals 1.5-3 mm, apex acute to acuminate		37 R. kirilowii
56 (54)	Stem leaves rhombic-ovate to elliptic		29 R. calliantha
+	Stem leaves not as above.		(57)
57 (56)	Flowering stems not leafy apically; stem leaves short, broadest near base.		(58)
+	Flowering stems leafy apically; stem leaves long, usually broadest in distal 1/2.		(59)
58 (57)	Leaf base cordate, amplexicaul, apex acute; sepals linear, ca. 7 × 1.3 mm; stamens reddish		34 R. heterodonta
+	Leaf base truncate to subcordate, apex shortly acuminate; sepals triangular-linear, ca. 1.1 × 1.3 mm; stamens yellow		35 R. junggarica
59 (57)	Flowering stems apically papillate; stem leaf margin serrate		33 R. serrata
+	Flowering stems smooth; stem leaf margin subentire, apically sometimes dentate.		(60)
60 (59)	Persistent old flowering stems and branches black when dry		32 R. crenulata
+	Persistent old flowering stems and branches not black when dry.		(61)
61 (60)	Plants 20-30 cm tall; stem leaves elliptic-lanceolate, oblong, or broadly oblong-ovate; sepals ca. 1/3 as long as petals		30 R. rosea
+	Plants 10-15 cm tall; stem leaves oblong-spatulate, oblong-lanceolate, or oblong-rhombic; sepals ca. 1/2 as long as petals		31 R. sachalinensis