1	Leaves verticillate or both opposite and alternate (all leaves alternate in S. chauveaudii var. margaritae).		(2)
+	Leaves alternate (sometimes opposite in S. blepharophyllum).		(8)
2 (1)	Inflorescences cymose-scorpioid; flowers sessile or subsessile; sepals broadly ovate to suboblong, equal, ca. 1.5 mm		72 S. chuhsingense
+	Inflorescences corymbiform; flowers shortly pedicellate; sepals sublinear, unequal, 3-6.5 mm.		(3)
3 (2)	Plants annual or biennial.		(4)
+	Plants perennial.		(5)
4 (3)	Styles ca. 1.8 mm; nectar scales broadly linear-spatulate		70 S. leblancae
+	Styles ca. 0.5 mm; nectar scales quadrangular		71 S. tsiangii
5 (3)	Leaves both verticillate and alternate; placenta subfalcate		66 S. bergeri
+	Leaves all verticillate (alternate in S. chauveaudii var. margaritae); placenta not subfalcate.		(6)
6 (5)	Petals ± free, apex papillate		69 S. dielsii
+	Petals basally connate for more than 1.5 mm, apex not papillate.		(7)
7 (6)	Sepals linear-spatulate; petals basally connate for ca. 1.5 mm		67 S. chauveaudii
+	Sepals linear-lanceolate; petals basally connate for 2-3 mm		68 S. tsonanum
8 (1)	Seed funicle inflated at base, appendage stomach-shaped.		(9)
+	Seed funicle not inflated at base.		(16)
9 (8)	Sepals spurless.		(10)
+	Sepals spurred.		(12)
10 (9)	Seeds covered with thick, chaffy scales		58 S. ramentaceum
+	Seeds minutely papillate or hairy.		(11)
11 (10)	Follicles 2- or 3-seeded; seeds minutely hairy		59 S. trichospermum
+	Follicles 12-14-seeded; seeds minutely papillate		60 S. prasinopetalum
12 (9)	Leaves and sepals acuminate to cuspidate apically; petals 2-2.3 mm		65 S. erici-magnusii
+	Leaves and sepals obtuse to sometimes subacute apically; petals 4-7.2 mm.		(13)
13 (12)	Sepals of terminal flower in 2 series		64 S. didymocalyx
+	Sepals in 1 series.		(14)
14 (13)	Leaves oblong to subovate; nectar scales 1.6-1.8 mm		61 S. forrestii
+	Leaves linear-oblong, linear-lanceolate, or linear-obovate; nectar scales 0.4-0.7 mm.		(15)
15 (14)	Leaves linear-lanceolate to linear-obovate; petals 4-6 mm; follicles 4- or 5-seeded		62 S. perrotii
+	Leaves linear-oblong; petals 7-7.2 mm; follicles usually ca. 7-seeded		63 S. longifuniculatum
16 (8)	Placenta inflated, falcate to lunate.		(17)
+	Placenta not inflated, rarely falcate to lunate.		(31)
17 (16)	Plants perennial; sterile stems present.		(18)
+	Plants annual or biennial; sterile stems absent.		(21)
18 (17)	Flowers 5-merous; petals ca. 3.5 mm, apex obtuse		43 S. muyaicum
+	Flowers unequally 5-merous; petals 5.8-9 mm, apex acuminate.		(19)
19 (18)	Underground stems absent; basal spur of leaves truncate-obtuse		46 S. longyanense
+	Underground stems present; basal spur of leaves obtuse or 3-lobed.		(20)
20 (19)	Sepals 6.5-7.2 mm, spurless		44 S. celiae
+	Sepals 3.5-5 mm, spurred		45 S. dugueyi
21 (17)	Sepals spurless at base.		(22)
+	Sepals spurred at base.		(25)
22 (21)	Nectar scales broadly spatulate, ca. 0.4 mm, apically appendaged; leaf apex acuminate		47 S. celatum
+	Nectar scales narrowly linear to linear-spatulate, 0.7-1.3 mm, apically not appendaged; leaf apex obtuse.		(23)
23 (22)	Nectar scales 0.8-1.3 mm; follicles 3-6-seeded; stamens 5		48 S. przewalskii
+	Nectar scales ca. 0.7 mm; follicles 1-3-seeded; stamens 10.		(24)
24 (23)	Petals narrowed toward base, apex obscurely mucronate; placenta lunulate		49 S. pagetodes
+	Petals broadened toward base, apex not mucronate; placenta basal		50 S. pratoalpinum
25 (21)	Leaves broadened in distal 1/2 (sometimes not so in S. sinoglaciale); nectar scales 1-1.5 mm.		(26)
+	Leaves broadened in proximal 1/2; nectar scales 0.5-0.8 mm.		(28)
26 (25)	Follicles 2-seeded; antepetalous stamens inserted 1-1.2 mm from petal base; seeds smooth		57 S. semilunatum
+	Follicles 5- to many seeded; antepetalous stamens inserted ca. 2 mm from petal base; seeds papillate.		(27)
27 (26)	Carpels basally connate for 1.2-1.8 mm; basal leaves spatulate, others subpanduriform; sepals obtuse at apex		55 S. chingtungense
+	Carpels ± free; leaves linear to linear-oblong; sepals acute at apex		56 S. sinoglaciale
28 (25)	Nectar scales apically parted to lobate; leaf apex obtuse; follicles 2-4-seeded		54 S. purdomii
+	Nectar scales apically obtuse or retuse; leaf apex acute to acuminate; follicles (3-)7-12-seeded.		(29)
29 (28)	Petals ca. 4 mm, ± free		53 S. fedtschenkoi
+	Petals 6-10.5 mm, basally subconnate.		(30)
30 (29)	Petals yellow; placenta falcate; follicles 10-12-seeded		51 S. paracelatum
+	Petals purplish red; placenta sublunulate; follicles 7-9-seeded		52 S. luchuanicum
31 (16)	Petals abruptly narrowed basally or attenuate into a claw.		(32)
+	Petals neither narrowed basally nor attenuate into claw.		(36)
32 (31)	Plants annual or biennial; sterile stems absent.		(33)
+	Plants perennial; sterile stems present.		(34)
33 (32)	Sepals lanceolate to lanceolate-oblong; petals red, obtrullate; stamens often 5		41 S. obtrullatum
+	Sepals ovate to ovate-oblong; petals yellow, narrowly oblong; stamens 10		42 S. raymondii
34 (32)	Petal claw broad, less than 3 mm; sepals spurred, margin papillate		38 S. gagei
+	Petal claw narrow, to 4 mm; sepals spurless, margin laevigate.		(35)
35 (34)	Petals sagittate, limb subovate, attenuate in distal 1/2, apex narrowly apiculate		39 S. sagittipetalum
+	Petals trullate, limb ovate-lanceolate to broadly ovate, basally narrowed, apex mucronate		40 S. trullipetalum
36 (31)	Petals basally connate for more than 1 mm (for ca. 0.8 mm in S. costantinii); stamens in 2 series.		(37)
+	Petals free or basally subconnate usually for less than 1 mm; stamens in 1 or 2 series.		(42)
37 (36)	Petal margin erose or suberose.		(38)
+	Petal margin entire.		(39)
38 (37)	Petals lanceolate to oblong, margin conspicuously erose; leaves linear, apex spinose-apiculate; sepals spurless, apex spinose-apiculate		9 S. daigremontianum
+	Petals obovate-lanceolate to obovate, margin ± erose; leaves lanceolate to broadly oblong, apex acute; sepals spurred, apex acute		10 S. oreades
39 (37)	Petals ca. 11 mm		12 S. feddei
+	Petals 5-6.2 mm		(40)
40 (39)	Sepals yellowish green; leaf base spur 3-lobed		11 S. costantinii
+	Sepals green; leaf base spur entire.		(41)
41 (40)	Petal base clawless, apex long mucronate; sepals linear or subspatulate		13 S. fui
+	Petal base ± clawed, apex subacuminate; sepals suboblong		14 S. wangii
42 (36)	Leaf apex obtuse; stamens 5-10(-12).		(43)
+	Leaf apex acuminate to acute; stamens 10 (sometimes 5 in S. ulricae).		(52)
43 (42)	Sepals spurless.		(44)
+	Sepals spurred.		(47)
44 (43)	Flowers 5-merous; plants less than 2.5 cm tall.		(45)
+	Flowers unequally 5-merous; plants 3.5-6 cm tall.		(46)
45 (44)	Plants 1-2.5 cm tall; leaves narrowly oblong; follicles 6-8(-14)-seeded; seeds minutely papillate		28 S. fischeri
+	Plants ca. 10 mm tall; leaves ovate to suborbicular; follicles 1- or 2-seeded; seeds winged at both ends		29 S. oligocarpum
46 (44)	Leaves broadly linear to oblong; follicles few seeded		30 S. lutzii
+	Leaves ovate; follicles 6- or 7-seeded		31 S. tsinghaicum
47 (43)	Seeds smooth, winged; leaf and sepal margin smooth; follicles 10-12-seeded		37 S. magniflorum
+	Seeds papillate, wingless; leaf and sepal margin papillate; follicles more than 12-seeded.		(48)
48 (47)	Petals basally free or almost so.		(49)
+	Petal basally subconnate.		(50)
49 (48)	Petal apex smooth; nectar scales apically emarginate; follicles 12-15-seeded		32 S. roborowskii
+	Petal apex papillate; nectar scales apically rounded; follicles 20-22-seeded		33 S. blepharophyllum
50 (48)	Leaves broadly lanceolate to lanceolate-oblong; petal apex papillate		34 S. obtusipetalum
+	Leaves obovate, obovate-oblong, or suboblong; petal apex smooth.		(51)
51 (50)	Petals broadly triangular; sepal apex rounded; stamens 5 or 10		35 S. somenii
+	Petals narrowly oblong; sepal apex obtuse; stamens 10		36 S. morotii
52 (42)	Plants perennial; sterile stems numerous.		(53)
+	Plants annual or biennial; sterile stems absent (present in S. susanneae).		(58)
53 (52)	Leaf base spur obtuse or truncate.		(54)
+	Leaf base spur lobed to sublobed.		(55)
54 (53)	Sepals spurless; petals basally almost free; basal leaves of flowering stems ovate-lanceolate, persistent; seeds winged		19 S. barbeyi
+	Sepals spurred; petals basally connate for ca. 1.2 mm; basal leaves of flowering stems linear, soon withered; seeds wingless		20 S. pampaninii
55 (53)	Spur 2-lobed, occasionally ± 3-lobed; leaf and sepal margin glandular ciliate		18 S. glaebosum
+	Spur 3-lobed or ± so (sometimes truncate in S. heckelii); leaf and sepal margin glabrous.		(56)
56 (55)	Sepals spurless, adaxially papillate		15 S. beauverdii
+	Sepals spurred, adaxially smooth.		(57)
57 (56)	Inflorescences dense; sepals narrowly oblong to ovate, apex shortly acuminate		16 S. heckelii
+	Inflorescences lax; sepals lanceolate to narrowly triangular, apex acuminate		17 S. nothodugueyi
58 (52)	Sepals spurless.		(59)
+	Sepals spurred.		(60)
59 (58)	Leaf and sepal margin glabrous; carpels glabrous		21 S. susanneae
+	Leaf and sepal margin spinescent ciliate; carpels adaxially spinescent hairy		22 S. stimulosum
60 (58)	Petals 6.5-8.9 mm.		(61)
+	Petals less than 4.5 mm.		(62)
61 (60)	Pedicel 1-2 mm; sepals linear-lanceolate or subovate; petals apex long mucronate		23 S. rosei
+	Pedicel 6-10 mm; sepals oblong; petal apex acuminate		24 S. platysepalum
62 (60)	Petals ca. 3 mm, basally connate, apex mucronulate		27 S. henrici-robertii
+	Petals to 4.5 mm, free, apex not mucronulate.		(63)
63 (62)	Plants 10-13 cm tall; carpels suberect		25 S. franchetii
+	Plants 3-6 cm tall; carpels divergent		26 S. ulricae