1	Petals 5--7-cleft, longer than sepals		58 S. radians
+	Petals 2-cleft either apically or often to base, longer or shorter than sepals, seldom absent.		(2)
2 (1)	Styles 2(or 3) or 4; capsules 4(or 6)-valved.		(3)
+	Styles usually 3; capsules usually 6-valved.		(7)
3 (2)	Styles 4.		(4)
+	Styles 2(or 3).		(5)
4 (3)	Sepals rounded apically		64 S. strongylosepala
+	Sepals long acuminate apically		45 S. oxycoccoides
5 (3)	Petals and sepals 4; stamens 8; petals ca. 1.5 × as long as sepals; styles 2		59 S. martjanovii
+	Petals and sepals 5; stamens 10; petals shorter than the sepals; styles 2(or 3).		(6)
6 (5)	Stems 0.1--0.3 m, tufted; leaves oblong-lanceolate, 0.1--0.2 cm		63 S. bistyla
+	Stems 1--2 m, diffuse; leaves ovate-lanceolate, (2--)3--10 cm		61 S. ovatifolia
7 (2)	Seeds 1--3(--8), ovules few or many; capsules shorter than sepals, often globose; stamens (5--)8--10.		(8)
+	Seeds and ovules many (rarely few); capsules usually subequaling or longer than sepals, often ovoid; stamens (2--)10, hypogynous or perigynous.		(19)
8 (7)	Stems 15--20 cm tall, not tufted; inflorescence bracts absent; petals ca. 2 × as long as sepals		25 S. ebracteata
+	Stems 2--200 cm, tufted if less than 30 cm; inflorescence bracts present; petals shorter than sepals or absent.		(9)
9 (8)	Stems 50--200 cm, diffuse; leaves lanceolate to oblong- or ovate-lanceolate, (2--)3--11(--23) cm; young ovary 3-loculed, with 3 or 4 ovules.		(10)
+	Stems 2--30(--60) cm, tufted, plants often cushionlike; leaves linear or ovate, 0.3--3.5 cm; ovary 1-loculed, ovules many.		(12)
10 (9)	Stamens 5; capsule with 2 or 3 mature seeds; petals subequaling sepals		62 S. delavayi
+	Stamens 5 or 10; capsule with 1 mature seed; petals shorter than sepals.		(11)
11 (10)	Plants glandular hairy; leaves lanceolate to oblong-lanceolate, base rounded, semiclasping; petals ca. 2/3 as long as sepals		60 S. monosperma
+	Plants pubescent with curved hairs; leaves ovate-lanceolate, base narrowed into petiole; petals minute, ca. 1/3 as long as sepals		61 S. ovatifolia
12 (9)	Petals 2-cleft to middle; plants glandular hairy; stamens 10.		(13)
+	Petals 2-cleft nearly to base or absent; plants densely cushionlike, glabrous or pubescent or woolly; stamens 5 or (8--)10.		(14)
13 (12)	Sepals lanceolate, apex acuminate, margin narrowly membranous; stems terete		22 S. dichotoma
+	Sepals oblong, apex obtuse, margin broadly membranous; stems quadrangular		23 S. amblyosepala
14 (12)	Petals subequaling sepals; stamens 5		12 S. petiolaris
+	Petals shorter than sepals or absent; stamens (8--)10.		(15)
15 (14)	Leaves ovate to ovate-lanceolate, 3--6 mm.		(16)
+	Leaves linear to linear-lanceolate, 4--20(--25) mm.		(17)
16 (15)	Plants 5--7 cm tall; stems glabrous basally, pubescent apically		53 S. arenarioides
+	Plants 10--20 cm tall; stems densely white pubescent, rarely glabrous		56 S. decumbens
17 (15)	Stems glabrous		55 S. petraea
+	Stems pubescent, either with curved hairs or white pilose apically.		(18)
18 (17)	Stems pubescent with curved hairs; flowers few in loose cymes		54 S. cherleriae
+	Stem white lanate apically; flowers many in dense cymes		57 S. congestiflora
19 (7)	Sepals distinct; stamens hypogynous or perigynous.		(20)
+	Sepals connate at base into obconic calyx; stamens perigynous.		(41)
20 (19)	Leaves linear-lanceolate; petals ca. 1.5 × as long as sepals		24 S. henryi
+	Leaves broader, usually ovate or ovate-lanceolate; petals of varying lengths.		(21)
21 (20)	Leaves sessile or subsessile, base sometimes slightly clasping.		(22)
+	All leaves or only leaves of lower stems petiolate.		(29)
22 (21)	Plants glabrous		17 S. gyirongensis
+	Plants hairy.		(23)
23 (22)	Plants stellate hairy		16 S. infracta
+	Plants pubescent, hairs not stellate.		(24)
24 (23)	Plants pubescent, hairs short, not dense; abaxial leaf midvein prominent.		(25)
+	Plants glandular hairy, woolly, or hairs long filiform; abaxial leaf midvein prominent or not.		(26)
25 (24)	Leaves with inconspicuous reticulate abaxial veins, only basal margin ciliate; sepals 2--2.5 mm		14 S. omeiensis
+	Leaves with conspicuous reticulate abaxial veins, margin ciliate; sepals ca. 2.5 mm		15 S. reticulivena
26 (24)	Plants densely glandular hairy.		(27)
+	Plants woolly or with long hairs.		(28)
27 (26)	Leaves ovate, 5--15 mm, margin ciliate; petals 2-cleft to base; seeds rugulose		18 S. zangnanensis
+	Leaves oblong, 12--18 mm, margin not ciliate; petals 2-cleft to middle; seeds tuberculate		19 S. tibetica
28 (26)	Plants densely white woolly; petals shorter than sepals; stamens 8; capsules ca. 2 × as long as persistent sepals		20 S. lanata
+	Plants long filiform hairy; petals nearly as long as sepals; stamens 10; capsules shorter than persistent sepals		21 S. patens
29 (21)	Cymes with few flowers or flower solitary and axillary; petals slightly longer than sepals, 2-cleft to base or 2-lobed.		(30)
+	Cymes usually with numerous flowers; petals shorter than or subequaling sepals, sometimes very small or absent.		(34)
30 (29)	Stems glabrous; petals apically 2-cleft only to 1/3; flowers of 2 types: lower axillary flowers lacking stamens (and petals)		5 S. wushanensis
+	Stems hairy; petals 2-lobed or 2-cleft to base; flowers uniform.		(31)
31 (30)	Stems glandular hairy; leaves ovate or ovate-oblong, 2--8 cm.		(32)
+	Stem hairs not glandular; leaves ovate to rhombic, 0.5--1.5 cm.		(33)
32 (31)	Capsule slightly longer than sepals; stem with 1 line of multicellular glandular hairs; sepals ovate-oblong to ovate-lanceolate, apex obtuse		1 S. bungeana var. stubendorfii
+	Capsule 1.5--2 × as long as sepals; stem sparsely glandular hairy; sepals lanceolate, apex acute		2 S. nemorum
33 (31)	Stems with appressed hairs; leaves ovate, apex obtuse, base rounded, shortly petiolate or sessile; petals 2-cleft nearly to base		3 S. nepalensis
+	Stems sparsely stiffly hairy; leaves rhombic or triangular-ovate, apex acuminate, base rounded or nearly cordate; petals 2-lobed		4 S. arisanensis
34 (29)	Plants with 1(or 2) lines of hairs on stems or basal margin of leaves and nodes, not pilose or stellate hairy.		(35)
+	Plants stellate hairy or pilose, rarely glabrous.		(37)
35 (34)	Petals absent or very small; stamens 3--5; seeds 0.7--0.8 mm in diam., with tiny protuberances		8 S. pallida
+	Petals present, shorter than or subequaling sepals; stamens 3--10; seeds ca. 1 mm or more in diam., with conic or semiglobose protuberances.		(36)
36 (35)	Stems somewhat stout, 30--80 cm tall; petals subequaling sepals; stamens (6--)8--10; seeds ca. 1.5 mm in diam., with conic protuberances		6 S. neglecta
+	Stems slender, 10--30 cm tall; petals shorter than or subequaling sepals; stamens 3--5; seeds 1--1.2 mm in diam., with semiglobose protuberances		7 S. media
37 (34)	Plants stellate hairy		9 S. vestita
+	Plants pilose or only petioles pilose, rarely glabrous.		(38)
38 (37)	Leaves ovate to ovate-lanceolate, glabrous on both surfaces, sometimes reddish green		10 S. chinensis
+	Leaves narrowly ovate to oblong-lanceolate, white hairy on both surfaces, rarely glabrous.		(39)
39 (38)	Petals absent; leaves lanceolate to linear-lanceolate		13 S. lanipes
+	Petals present; leaves oblong-lanceolate to narrowly ovate.		(40)
40 (39)	Leaves oblong-lanceolate, 2.5--4 cm; petals slightly shorter than sepals; stamens 10		11 S. pilosoides
+	Leaves narrowly ovate, 1.5--2.5 cm; petals subequaling sepals; stamens 5		12 S. petiolaris
41 (19)	Flowers solitary, axillary or terminal; bracts herbaceous, without membranous margin; pedicels filiform, curved after anthesis; stems glabrous.		(42)
+	Flowers in cymes or umbels, rarely solitary; bracts all herbaceous or with membranous margin; pedicels not filiform; stems glabrous or not.		(43)
42 (41)	Plants usually less than 5 cm tall; stamens subequaling petals		26 S. winkleri
+	Plants 5--14 cm; stamens shorter than petals		27 S. crassifolia
43 (41)	Flowers in cymose umbels; petals absent or small.		(44)
+	Flowers in dichotomous cymes, rarely solitary; petals present (rarely absent), usually conspicuous.		(47)
44 (43)	Petals small; inflorescence compact; stems less than 5 cm tall		49 S. irrigua
+	Petals absent; inflorescence loose; stems 5--20 cm tall.		(45)
45 (44)	Stems pilose; leaves ovate-lanceolate to ovate		50 S. parviumbellata
+	Stems glabrous; leaves elliptic or linear to linear-lanceolate.		(46)
46 (45)	Stems tufted; leaves linear to linear-lanceolate; stamens 5		52 S. subumbellata
+	Stems solitary; leaves elliptic; stamens 10		51 S. umbellata
47 (43)	Leaves lanceolate to narrowly ovate, base semiclasping.		(48)
+	Leaves narrower, linear to linear-lanceolate; base semiclasping or not.		(53)
48 (47)	Plants glabrous; leaves lanceolate.		(49)
+	Plants pubescent; leaves lanceolate to ovate-lanceolate.		(51)
49 (48)	Leaf margin herbaceous; stamens 10		28 S. discolor
+	Leaf margin cartilaginous, crisp; stamens 5(--10).		(50)
50 (49)	Leaves (2--)5--20 mm; stamens 5(--10)		33 S. alsine
+	Leaves 30--60 mm; stamens 10		38 S. salicifolia
51 (48)	Leaves lanceolate or narrowly ovate, 4--12 mm, base narrowed; inflorescences with 1--3 flowers		30 S. pusilla
+	Leaves ovate-lanceolate, 3--10 mm; inflorescences with numerous flowers.		(52)
52 (51)	Leaf apex acute; stems with retrorse hairs; petals slightly longer than sepals; pedicel 5--30 mm, longer than sepals		31 S. mainlingensis
+	Leaf apex obtuse; stems minutely pubescent; petals shorter than sepals (rarely absent); pedicel 3--4 mm, subequaling sepals		32 S. depressa
53 (47)	Flower solitary; mature capsule black		48 S. soongorica
+	Inflorescences with numerous flowers; mature capsule yellow.		(54)
54 (53)	Stems pubescent.		(55)
+	Stems glabrous or nearly so.		(59)
55 (54)	Stems pubescent, hairs retrorse		44 S. alaschanica
+	Stem pubescence not retrorse.		(56)
56 (55)	Stems not tufted.		(57)
+	Stems tufted.		(58)
57 (56)	Stems minutely pubescent; leaves linear, sickle-shaped		29 S. gyangtseensis
+	Stems with 2 lines of hairs; leaves linear to linear-lanceolate, not sickle-shaped		34 S. graminea
58 (56)	Stems densely tufted, 5--15 cm tall, with one line of recurved hairs; petals ca. 2/3 as long as sepals		46 S. uda
+	Stems sparsely tufted, 20--30 cm tall, sparsely hairy; petals slightly shorter than or subequaling sepals		47 S. souliei
59 (54)	Petals 1/2--2/3 as long as the sepals; leaves lanceolate, 1--2 cm		35 S. brachypetala
+	Petals slightly shorter than to 2 × as long as sepals; leaves linear to lanceolate.		(60)
60 (59)	Abaxial midvein of leaf blade inconspicuous, not raised.		(61)
+	Abaxial midvein of leaf blade conspicuously raised.		(63)
61 (60)	Leaves oblong-lanceolate, ca. 1 cm, apex obtuse, margin glabrous; flowers 1 or 2; petals slightly longer than sepals		41 S. imbricata
+	Leaves linear to lanceolate, 0.5--7 cm, apex acute, margin usually ciliate; flowers numerous; petals slightly shorter to longer than sepals.		(62)
62 (61)	Leaves 0.5--4 cm, margin ciliate at base; seeds black-brown, granulose		34 S. graminea
+	Leaves 3--5(--7) cm, margin ciliate; seeds brown, sparsely tuberculate		36 S. yunnanensis
63 (60)	Stems rough; leaf margin finely papillate roughened, rarely sparsely ciliate.		(64)
+	Stems smooth; leaf margin often ciliate, especially near base of blade.		(65)
64 (63)	Sepals ca. 3 mm or less at anthesis, apex obtuse, veins inconspicuous; mature capsule black-brown; seeds smooth		40 S. longifolia
+	Sepals (4--)5 mm or more at anthesis, apex acuminate, veins conspicuous; mature capsule yellowish; seeds rugulose		37 S. palustris
65 (63)	Pedicels ca. 15 mm or less; sepals 6--7 mm; petals shorter than sepals		39 S. dianthifolia
+	Pedicels ca. 14 mm or longer; sepals 4--5.5 mm; petals subequaling to 2 × as long as sepals.		(66)
66 (65)	Seeds orbicular-reniform, tuberculate; petals 1.5--2 × as long as sepals		42 S. nipponica
+	Seeds ellipsoid, rugulose; petals subequaling to 1.5 × as long as sepals		43 S. filicaulis