Key to sections based on vegetative characters

1	Dwarf shrubs erect, ascending, procumbent, creeping, or cushion-shaped, usually less than 30(-50) cm tall.		(2)
+	Shrubs or trees erect, more than 30 cm tall.		(9)
2 (1)	Leaves adaxially white woolly, at least some young branchlets white woolly in autumn		31 Sect. Subviminales
+	Leaves and young branchlets not white woolly.		(3)
3 (2)	Petiole more than 1/4 as long as leaf blade.		(4)
+	Petiole less than 1/4 as long as leaf blade.		(5)
4 (3)	Leaves more than 2 cm		20 Sect. Diplodictyae
+	Leaves less than 2 cm		11 Sect. Lindleyanae
5 (3)	Plant erect or ascending.		(6)
+	Plant creeping or cushion-shaped.		(7)
6 (5)	Branchlets brown or dull brown to nearly black		10 Sect. Floccosae
+	Branchlets light brown		7 Sect. Fulvopubescentes
7 (5)	Leaf blade entire at margin, rarely crenate, at least some retuse at apex (or long obovate and acute at apex:		23 Sect. Arbuscella
+	Leaf blade dentate at margin, at least some sparsely serrate toward apex, usually not retuse at apex.		(8)
8 (7)	Leaves with sharply pointed, nearly spinose teeth at margin or, if glandular serrulate, then generally 2-3 × 1-2 cm		21 Sect. Myrtosalix
+	Leaves less than 1.5 cm, without spinose teeth at margin		7 Sect. Fulvopubescentes
9 (1)	Leaf blade green, at least 5 × as long as wide, usually linear, lanceolate, or oblong-lanceolate.		(10)
+	Leaf blade rarely slightly grayish blue, less than 5 × as long as wide, often elliptic to suborbicular or oblong to obovate-oblong.		(36)
10 (9)	Leaf blade entire, subentire, or sinuolate (sometimes serrate in		8 Sect. Magnificae
+	Leaf blade serrate.		(25)
11	Leaves abaxially pilose (or with rudimentary, comose indumentum along midvein).		(12)
+	Leaves abaxially glabrous (or slightly downy along midvein).		(21)
12 (11)	Leaves abaxially brown or white downy, at least pilose along veins		7 Sect. Fulvopubescentes
+	Leaves abaxially sericeous, white tomentose, or with rudimentary, comose indumentum or, if downy, then narrow and small, to 4.5 cm × 1-3 mm.		(13)
13 (12)	Leaves in distal 1/2 of branchlets usually less than 5 cm (rarely slightly longer), abaxially with yellowish brown hairs, white sericeous, or ± silky.		(14)
+	Leaves in distal 1/2 of branchlets usually more than 5 cm, abaxially sericeous, tomentose or with rudimentary, comose indumentum, rarely pilose.		(16)
14 (13)	Leaf blade in distal 1/2 of branchlets (8-)9(-21) × as long as wide; branchlets usually red or reddish black, downy or glabrous		34 Sect. Cheilophilae
+	Leaf blade in distal 1/2 of branchlets 5-8 × as long as wide; branchlets densely brown tomentose.		(15)
15 (14)	Branchlets ca. 1 mm thick, densely yellowish brown tomentose; plants 50-80 cm tall, growing in marshes		29 Sect. Incubaceae
+	Branchlets more than 2 mm thick, yellowish brown, dull colored, or grayish white tomentose; plants more than 1 m tall, not growing in marshes		14 Sect. Eriocladae
16 (13)	Leaf blade broadly linear to linear-lanceolate (oblong on shoots of S.rehderiana)		28 Vimen
+	Leaf blade lanceolate or obovate-lanceolate, rarely narrowly obovate.		(17)
17 (16)	Leaves abaxially sparsely silky or downy; ovary glabrous, shortly stipitate.		(18)
+	Leaves abaxially densely sericeous or tomentose, or with rudimentary, comose indumentum along midvein; ovary pilose, sessile.		(19)
18 (17)	Leaves to 10 cm		9 Sect. Denticulatae
+	Leaves more than 10 cm		8 Sect. Magnificae
19 (17)	Leaf blade linear to linear-lanceolate		28 Vimen
+	Leaf blade not linear to linear-lanceolate.		(20)
20 (19)	Leaf blade lanceolate or broadly lanceolate to oblanceolate, to 6 cm, abaxially yellowish tomentose		14 Sect. Eriocladae
+	Leaf blade lanceolate to elliptic-lanceolate, usually more than 6 cm, abaxially not yellowish tomentose		13 Sect. Psilostigmatae
21 (11)	Leaf margin sinuolate or revolute		28 Vimen
+	Leaf margin neither sinuolate nor revolute.		(22)
22 (21)	Leaves usually more than 5 cm.		(23)
+	Leaves usually less than 5 cm.		(24)
23 (22)	Leaf blade (10-)15-20 × 3-5 cm		8 Sect. Magnificae
+	Leaf blade to 15 × 3 cm		36 Helix
24 (22)	Leaves abaxially pale; ovary glabrous		9 Sect. Denticulatae
+	Leaves abaxially light green; ovary hairy		12 Sect. Sclerophyllae
25 (10)	Leaf apex obtuse or acute to shortly acuminate or, if acuminate, then margin thickened, bonelike, with glandular teeth; shrubs, rarely small trees.		(26)
+	Leaf apex long acuminate or acuminate (acute in S. tengchongensis); trees.		(31)
26 (25)	Leaf blade ca. 17 × 1-4.5 cm		13 Sect. Psilostigmatae
+	Leaf blade smaller.		(27)
27 (26)	Leaf blade margin with densely regularly spaced teeth 4 or 5 per cm		5 Sect. Amygdalinae
+	Leaf blade margin remotely dentate, teeth more remote and inconspicuous toward leaf base.		(28)
28 (27)	Young branchlets and leaves glabrous; stipules linear.		(29)
+	Young branchlets and leaves tomentose; stipules lanceolate, rarely reniform or ovate.		(30)
29 (28)	Mature leaf blade more than 3 mm wide, usually broadest above middle		36 Helix
+	Mature leaf blade less than 3 mm wide, usually more than 8 cm, proximal and distal parts nearly equally wide		37 Sect. Flavidae
30 (28)	Mature leaf blade (4-)5-6(-8) × as long as wide		35 Sect. Haoanae
+	Mature leaf blade 3-4(-5) × as long as wide		31 Sect. Subviminales
31 (25)	Distal part of petiole ± glandular.		(32)
+	Distal part of petiole eglandular.		(33)
32 (31)	Stipules small, subulate, caducous; young branchlets and leaves very viscid		4 Sect. Pentandrae
+	Stipules developed, especially on shoots, semicordate or semiovate-lanceolate; young branchlets and leaves not or only slightly viscid		3 Wilsonia
33 (31)	Stipules small, subulate, semicordate-lanceolate, or caducous; branchlets usually slender, weak, pendulous or ± pendulous		6 Sect. Salix
+	Stipules ovate-lanceolate, ovate, broadly ovate, or semicordate; branchlets thick, not pendulous.		(34)
34 (33)	Juvenile branchlets glabrous; buds longer than petioles; leaf margin regularly serrulate		26 Sect. Daphnella
+	Juvenile branchlets ± pilose; buds shorter than petioles.		(35)
35 (34)	Leaves usually 9-10 cm		1 Sect. Tetraspermae
+	Leaves 2.4-6.5 cm		13 Sect. Psilostigmatae
36 (9)	Stipules semicordate, reniform, or suborbicular, large, broad, especially prominent on shoots, if semiovate or broadly lanceolate, then leaves slightly grayish blue.		(37)
+	Stipules neither semicordate, reniform, nor suborbicular, sometimes caducous.		(40)
37 (36)	Petiole glandular distally or, if eglandular, then leaf blade elliptic or oblong, abaxially silky, or ovate, basally cordate, with brown downy veins abaxially, or leaf margin serrulate or crenate-serrate		3 Wilsonia
+	Petiole eglandular distally.		(38)
38 (37)	Leaf blade orbicular, suborbicular, or rhombic-elliptic, abaxially often glabrous, margin serrate		22 Sect. Hastatae
+	Leaf blade broadly ovate, broadly elliptic, obovate, obovate-oblong, or elliptic to ovate-lanceolate, rarely suborbicular or, if lanceolate, then abaxially slightly grayish blue.		(39)
39 (38)	Leaves abaxially densely sericeous, with conspicuous, lateral veins, obovate-oblong or oblong		31 Sect. Subviminales
+	Leaves abaxially tomentose or glabrous, rarely silky, with indistinct, lateral veins, neither obovate-oblong nor oblong		24 Vetrix
40 (36)	Petiole on distal part of branchlets usually more than 1/4 as long as leaf blade; plant usually 30-50 cm tall.		(41)
+	Petiole on distal part of branchlets usually less than 1/4 as long as leaf blade; plants more than 50 cm tall.		(43)
41 (40)	Leaf blade dentate, rarely entire		10 Sect. Floccosae
+	Leaf blade entire.		(42)
42 (41)	Leaves more than 2 cm		20 Sect. Diplodictyae
+	Leaves less than 2 cm		12 Sect. Sclerophyllae
43 (40)	Leaves on distal 1/2 of branchlets less than 5 cm, those of a few species somewhat longer, with entire margins.		(44)
+	Leaves on distal part of branchlets more than 5 cm.		(61)
44 (43)	Leaves grayish blue, opposite or subopposite		32 Sect. Caesiae
+	Leaves not grayish blue, alternate.		(45)
45 (44)	Leaf blade (narrowly) oblong or narrowly obovate-oblong		33 Sect. Variegatae
+	Leaf blade neither oblong nor narrowly obovate-oblong.		(46)
46 (45)	Leaves adaxially conspicuously wrinkled		18 Sect. Chamaetia
+	Leaves adaxially smooth.		(47)
47 (46)	Leaves 1-2 cm, elliptic or oblong; 1-year-old branchlets ca. 1 mm thick; plants growing in marshes		17 Sect. Myrtilloides
+	Leaves usually more than 2 cm, variably shaped; 1-year-old branchlets more than 1 mm thick; plants not growing in marshes.		(48)
48 (47)	Nodes relatively expanded, forming beaded chains; internodes of branchlets usually less than 1 cm.		(49)
+	Nodes neither expanded nor forming beaded chains; internodes of branchlets more than 1 cm.		(50)
49 (48)	Mature leaf blade often obovate-oblong, ca. 3 × as long as wide; fallen leaves from previous year rust colored		31 Sect. Subviminales
+	Mature leaf blade variably shaped, usually elliptic, 1.5-2 × as long as wide; fallen leaves from previous year not rust colored		12 Sect. Sclerophyllae
50 (48)	Mature leaves abaxially pilose, at least with rudimentary hairs along veins abaxially.		(51)
+	Mature leaves abaxially glabrous.		(57)
51 (50)	Mature leaves abaxially densely sericeous.		(52)
+	Mature leaves abaxially neither densely sericeous nor with rudimentary hairs only along veins.		(55)
52 (51)	Leaf margin serrate distally		31 Sect. Subviminales
+	Leaf margin entire.		(53)
53 (52)	Leaves white pubescent or with hairs only along veins		25 Sect. Lanatae
+	Leaves sericeous.		(54)
54 (53)	Young leaves only abaxially sericeous		27 Sect. Argyraceae
+	Young leaves yellowish sericeous on both surfaces		29 Sect. Incubaceae
55 (51)	Juvenile branchlets pilose or, if glabrous, then most leaves aggregated at apex of branchlets		14 Sect. Eriocladae
+	Juvenile branchlets glabrous, or pilose when young, glabrescent; leaves lateral, not aggregated at apex of branchlets.		(56)
56 (55)	Branchlets russet		13 Sect. Psilostigmatae
+	Branchlets yellowish brown or brown		6 Sect. Salix
57 (50)	Leaves on distal part of branchlets entire or only dentate distally, entire proximally; ovary glabrous.		(58)
+	Leaves on distal part of branchlets dentate.		(59)
58 (57)	One-year-old branchlets ± pilose		9 Sect. Denticulatae
+	One-year-old branchlets glabrous		15 Sect. Heterochromae
59 (57)	Leaves grayish blue		19 Sect. Glaucae
+	Leaves not grayish blue.		(60)
60 (59)	Petiole 2-5 mm		22 Sect. Hastatae
+	Petiole 5-15 mm or, if less than 5 mm, then plants growing on Changbai Shan, NE China		23 Sect. Arbuscella
61 (43)	Leaf apex acute to acuminate.		(62)
+	Leaf apex acute, obtuse, or rounded.		(68)
62 (61)	Leaves often more than (9-)10 cm.		(63)
+	Leaves less than 9 cm.		(64)
63 (62)	Leaves abaxially light green or slightly white, with inconspicuous, reticulate veins (plants growing S of 23° N latitude)		1 Sect. Tetraspermae
+	Leaves abaxially white, with conspicuous, reticulate veins		2 Sect. Urbanianae
64 (62)	Leaves on at least distal part of branchlets silky abaxially		27 Sect. Argyraceae
+	Leaves abaxially neither silky nor glabrous.		(65)
65 (64)	Leaves entire or subentire.		(66)
+	Leaves dentate.		(67)
66 (65)	Branchlets densely tomentose, yellowish green; leaves abaxially often pilose; stipules ovate to lanceolate		25 Sect. Lanatae
+	Branchlets sparsely pilose or glabrous, usually reddish purple or reddish black; leaves pilose or glabrescent; stipules often caducous		15 Sect. Heterochromae
67 (65)	Glandular dots at tips of teeth not developed; young leaves not viscid, usually with brown hairs or downy		30 Sect. Sieboldianae
+	Glandular dots at tips of teeth developed; young leaves viscid, glabrous		4 Sect. Pentandrae
68 (61)	Leaf blade on distal part of branchlets usually more than 7 cm, usually broadest below middle, broadly ovate to suborbicular, abaxially glabrous; ovary glabrous		8 Sect. Magnificae
+	Leaf blade on distal part of branchlets usually less than 7 cm or, if longer, then abaxially pilose or at least pilose along veins, usually broadest above middle, obovate-elliptic to obovate-oblong, rarely elliptic or oblong-elliptic.		(69)
69 (68)	Leaves glabrous, with thin texture		23 Sect. Arbuscella
+	Leaves abaxially often pilose or glabrescent and with rudimentary hairs only along veins, rarely glabrous and then leaf blade relatively thick.		(70)
70 (69)	Leaves abaxially sericeous, shiny		31 Sect. Subviminales
+	Leaves abaxially tomentose or glabrous.		(71)
71 (70)	Juvenile branchlets pilose only on newly sprouted parts; 2-year-old branchlets glabrous, reddish purple or dark red, ca. 2 mm in diam.		15 Sect. Heterochromae
+	Juvenile branchlets pubescent; some 2-year-old branchlets pilose, not reddish purple, ca. 2.5 mm or more in diam.		(72)
72 (71)	Stipules caducous or inconspicuous		13 Sect. Psilostigmatae
+	Stipules prominent, ovate-lanceolate		25 Sect. Lanatae