1	Plants presumed introduced and widely naturalized in the flora area		(2)
+	Plants presumed native in the flora area		(12)
2 (1)	Stipules on late leaves absent or rudimentary		(3)
+	Stipules on late leaves foliaceous		(4)
3 (2)	Leaves and catkins alternate; branchlets densely pubescent or tomentose; largest medial blades: abaxial surface densely tomentose or woolly; floral bracts tawny or brown; ovaries glabrous; stipes 0.3-0.5 mm.		99 Salix elaeagnos
+	Leaves and catkins often opposite or subopposite; branchlets glabrous; largest medial blades: abaxial surface glabrous; floral bracts bicolor or black; ovaries short-silky; stipes 0-0.1 mm.		113 Salix purpurea
4 (2)	Petioles shallowly grooved adaxially		(5)
+	Petioles flat to convex adaxially		(7)
5 (4)	Branches yellow-brown, gray-brown, or yellowish; largest medial blades: abaxial surface apparently glaucous but obscured by hairs, margins strongly revolute, glands epilaminal; stigmas 0.72-1.8 mm.		98 Salix viminalis
+	Branches red-brown or gray-brown; largest medial blades: abaxial surface distinctly glaucous or not, margins sometimes slightly revolute or flat, glands submarginal or marginal; stigmas 0.3-0.68 mm		(6)
6 (5)	Branches not glaucous; stipules reniform, not adnate to petiole; largest medial blades broader, 1.1-2.8 times as long as wide, elliptic, broadly elliptic, subcircular or broadly obovate, apex abruptly acuminate or acute, abaxial surface often not glaucous apically.		75 Salix myrsinifolia (in part)
+	Branches strongly glaucous; stipules lanceolate to ovate, often adnate to petiole; largest medial blades 2.5-6.4 times as long as wide, lorate, oblong, narrowly elliptic or elliptic, apex gradually acuminate, abaxial surface uniformly and distinctly glaucous.		112 Salix daphnoides
7 (4)	Largest medial blades with veins strongly impressed adaxially; branchlets sometimes weakly glaucous, tomentose.		83 Salix aurita
+	Largest medial blades flat or with veins slightly impressed adaxially; branchlets not glaucous, puberulent, pubescent, pilose, villous, or velvety		(8)
8 (7)	Petioles puberulent or villous adaxially; branches red-brown, glabrous; catkins flowering as leaves emerge; ovaries glabrous or sparsely hairy.		75 Salix myrsinifolia (in part)
+	Petioles glabrescent, pubescent, tomentose, or velvety adaxially; branches yellowish, yellow-brown, or gray-brown, pubescent, pilose, villous, or tomentose to glabrescent; catkins flowering before leaves emerge; ovaries short- or long-silky		(9)
9 (8)	Peeled wood smooth or with striae to 6 mm; ovaries: beak gradually tapering to styles		(10)
+	Peeled wood with striae to 62 mm; ovaries: beak slightly bulged below styles		(11)
10 (9)	Largest medial blades usually 2-3 times as long as wide; branches flexible at base; stipes 2-2.5 mm; styles 0.3-0.6 mm; stigma lobes 0.4-0.6 mm.		80 Salix caprea
+	Largest medial blades usually 2.8-6.4 times as long as wide; branches ± brittle at base; stipes 0.9-2 mm; styles 0.5-1.2 mm; stigma lobes 0.6-1.2 mm [2e4. Salix sect. Cinerella]		Salix ×smithiana [p. 132]
11 (9)	Shrubs, 3-7(-10) m; largest medial blades: abaxial surface with white hairs; branches brownish, to 62 mm.		81 Salix cinerea
+	Shrubs or small trees, 3-12 m; largest medial blades: abaxial surface with white and ferruginous hairs; branches yellow-brown, gray-brown, or red-brown, to 45 mm.		82 Salix atrocinerea
12 (1)	Flowering before leaves emerge (sometimes just before in S. irrorata, S. myricoides, and S. tracyi); catkins usually sessile or on very short flowering branchlets (staminate 0-5 mm, to 9 mm in S. myricoides, pistillate 0-14 mm, to 35 mm in S. hookeriana)		(13)
+	Flowering as leaves emerge (staminate catkins sometimes emerge just before in S. irrorata, S. myricoides, and S. tracyi), catkins usually on distinct flowering branchlets (staminate 0-30 mm, pistillate 0.5-38 mm)		(54)
13 (12)	Ovaries glabrous		(14)
+	Ovaries hairy		(28)
14 (13)	Stipules usually marcescent		[2e9. Salix sect. Lanatae].
+	Stipules deciduous (in autumn)		(17)
15	Largest medial blades: apex acuminate, acute, or rounded; stipules 1-6-14 mm, 1.1-1.8-4.4 times as long as wide, usually ovate to oval or narrowly elliptic, pressing flat.		92 Salix calcicola
+	Largest medial blades: apex acute, acuminate, or convex; stipules 3-35 mm, 1.1-6 times as long as wide, shape variable, pressing with a pleat		(16)
16 (15)	Largest medial blades slightly glossy adaxially; floral bracts moderately densely hairy; pistillate adaxial nectaries 2+-lobed; stipules 3-12-35 mm, 1.7-3.6-6 times as long as wide, lanceolate or narrowly elliptic, sometimes ovate or oval.		93 Salix richardsonii
+	Largest medial blades dull adaxially; floral bracts sparsely hairy; pistillate adaxial nectaries unlobed; stipules 3.5-10-23 mm, 1-1.4- 2.8 times as long as wide, lanceolate, ovate, or suborbiculate.		94 Salix tweedyi
17 (14)	Largest medial blades dull adaxially		(18)
+	Largest medial blades slightly to highly glossy adaxially		(20)
18 (17)	Ovaries: beak slightly bulged below styles; styles 0.3-0.6 mm; floral bracts moderately to very densely hairy; east of 102d meridian.		68 Salix eriocephala (in part)
+	Ovaries: beak gradually tapering to styles; styles 0.5-1.8 mm; floral bracts sparsely hairy; usually west of 102d meridian		(19)
19 (18)	Petioles usually reddish; catkins usually sessile, flowering branchlets sometimes to 5 mm; juvenile blades glabrous or pubescent; stigmas 0.1-0.29 mm; stipes 0.5-3 mm; Canada to Montana, Black Hills of South Dakota, n Wyoming.		65 Salix pseudomonticola (in part)
+	Petioles green; catkins on distinct flowering branchlets 0.5-7 mm; juvenile blades villous or long-silky; stigmas 0.24-0.56 mm; stipes 0.5-1.6 mm; ne Arizona, Colorado, nw New Mexico, Utah, s Wyoming.		66 Salix monticola (in part)
20 (17)	Largest medial blades: margins often entire, sometimes irregularly serrate or crenate		(21)
+	Largest medial blades: margins regularly toothed		(24)
21 (20)	Largest medial blades usually 1.5-5.2 times as long as wide, bases often rounded to cordate; pistillate flowering branchlets 0-20 mm; styles distinct to 1/2 their lengths or connate, 0.3-2.3 mm; capsules 5-10 mm		(22)
+	Largest medial blades usually 1.9-9.6 times as long as wide, bases usually cuneate or convex; pistillate flowering branchlets 0-6 mm; styles connate, 0.1-0.9 mm; capsules 2.5-5.5 mm		[2e15. Salix sect. Mexicanae].
22 (21)	Pistillate catkins loosely flowered; pistillate flowering branchlets 1.5-13 mm; filaments glabrous; styles 0.3-1.3 mm; e North America.		67 Salix myricoides (in part)
+	Pistillate catkins densely flowered; pistillate flowering branchlets 0-20 mm; filaments hairy or glabrous; styles 0.6- 2.3 mm; w North America.		77 Salix hookeriana (in part)
23	Branches strongly glaucous; juvenile blades glabrous or sparsely villous; largest medial blades glabrous or pilose adaxially, hairs white.		104 Salix irrorata
+	Branches usually not glaucous, sometimes weakly so; juvenile blades sparsely to very densely tomentose, woolly or silky; largest medial blades glabrescent, tomentose, or short-silky adaxially, hairs usually white, sometimes also ferruginous.		105 Salix lasiolepis
24 (20)	Glands on largest medial blades submarginal		(25)
+	Glands on largest medial blades marginal		(26)
25 (24)	Pistillate catkins loosely flowered; pistillate flowering branchlets 1.5-13 mm; filaments glabrous; styles 0.3-1.3 mm; e North America.		67 Salix myricoides (in part)
+	Pistillate catkins densely flowered; pistillate flowering branchlets 0-20 mm; filaments hairy or glabrous; styles 0.6-2.3 mm; w North America.		77 Salix hookeriana (in part)
26 (24)	Petioles short-silky or velvety adaxially; staminate catkins not on flowering branchlets; floral bracts with straight hairs; ovules 18 per ovary.		65 Salix pseudomonticola (in part)
+	Petioles villous, tomentose, pilose, or pubescent adaxially; staminate catkins on flowering branchlets; floral bracts usually with wavy or curly hairs; ovules 12-16 per ovary		(27)
27 (26)	Largest medial blades with relatively very thick glaucescence abaxially, usually 2-5.2 times as long as wide; floral bracts brown to black; styles 0.3-1.3 mm; pistillate flowering branchlets 1.5-13 mm.		67 Salix myricoides (in part)
+	Largest medial blades with relatively thin glaucescence abaxially, usually 2.3-8 times as long as wide; floral bracts tawny or light brown; styles 0.3-0.6 mm; pistillate flowering branchlets 2-10 mm.		68 Salix eriocephala (in part)
28 (13)	Stipules on early leaves absent or rudimentary		(29)
+	Stipules on early leaves foliaceous (rarely so in S. drummondiana and S. pellita)		(41)
29 (28)	Ovaries obturbinate or squat, flask-shaped (serpentine endemics, California, Oregon)		[2e17. Salix sect. Sitchenses (in part)].
+	Ovaries pyriform or obclavate (not serpentine endemics)		(31)
30	Floral bracts usually tawny, densely hairy; largest medial blades lorate, very narrowly elliptic or oblanceolate, apex acuminate or acute; ovaries squat, flask-shaped, beak abruptly tapering to styles; branches flexible at base.		110 Salix breweri (in part)
+	Floral bracts brown, sparsely to moderately densely hairy; largest medial blades elliptic or obovate, apex convex or rounded; ovaries obturbinate, beak gradually tapering to styles; branches highly brittle at base.		111 Salix delnortensis (in part)
31 (29)	Largest medial blades highly glossy adaxially		(32)
+	Largest medial blades dull or slightly glossy adaxially		(35)
32 (31)	Ovaries villous, tomentose, or woolly; stipes 0.5-2.2 mm; anthers yellow (Alaska to n California).		77 Salix hookeriana (in part)
+	Ovaries silky; stipes 0.2-1.1 mm; anthers purple turning yellow in age		[2e6. Salix sect. Phylicifoliae (in part)].
33	Largest medial blades usually 4.2-11.3 times as long as wide, linear, lorate or narrowly elliptic, abaxial surface usually very densely villous, short-silky, tomentose, or woolly (sometimes sparsely so), glands marginal or epilaminal; petioles sometimes with 2 spherical glands distally; branches brittle at base.		86 Salix pellita (in part)
+	Largest medial blades usually 1.5-5.1 times as long as wide, obovate, oblanceolate, narrowly oblong, elliptic, or narrowly elliptic, abaxial surface glabrous or sparsely silky, glands marginal or submarginal; petioles without glands at base of blade; branches flexible at base		(34)
34 (33)	Largest medial blades usually hypostomatous (sometimes hemiamphistomatous).		88 Salix planifolia (in part)
+	Largest medial blades amphistomatous.		89 Salix tyrrellii (in part)
35 (31)	Stems decumbent, 0.3-3 m, layering, not glaucous or weakly so; largest medial blades: hairs white or gray; styles 0.2-0.4 mm; stigmas 0.2-0.56 mm.		78 Salix humilis (in part)
+	Stems erect, 0.5-6 m, not layering, often strongly glaucous; largest medial blades: hairs white, sometimes also ferruginous; styles 0.3-1.5 mm; stigmas 0.32-0.76 mm		(36)
36 (35)	Largest medial blades: abaxial surface often obscured by dense hairs		[2e6. Salix sect. Phylicifoliae (in part)].
+	Largest medial blades: abaxial surface not obscured by hairs		(38)
37	Petioles villous or velvety adaxially; largest medial blades usually 3-6.2 times as long as wide, glands submarginal; w North America.		85 Salix drummondiana
+	Petioles glabrous or pubescent adaxially; largest medial blades usually 4.2-11.3 times as long as wide, glands submarginal or epilaminal; e North America.		86 Salix pellita (in part)
38 (36)	Largest medial blades 4.2-11.3 times as long as wide, linear to narrowly elliptic; capsules 3.5-6.5 mm.		86 Salix pellita (in part)
+	Largest medial blades 1.5-4.5 times as long as wide, narrowly elliptic to obovate or broadly so; capsules 4.5-11 mm		[2e4. Salix sect. Cinerella (in part)].
39	Petioles and branchlets velvety; styles 0.2-0.6 mm; largest medial blades usually oblanceolate; ovaries densely long-silky.		79 Salix scouleriana (in part)
+	Petioles and branchlets not velvety; styles 0.3-2.3 mm; largest medial blades elliptic, oblanceolate, or obovate; ovaries moderately densely short-silky or densely villous, tomentose, or woolly		(40)
40 (39)	Stipes 1.6-2.7 mm; ovaries short-silky, hairs straight; styles 0.3-1 mm; pistillate flowering branchlets 0-10 mm; largest medial blades dull or slightly glossy adaxially, margins flat; primarily e North America to c British Columbia.		76 Salix discolor (in part)
+	Stipes 0.5-2.2 mm; ovaries villous, tomentose, or woolly, hairs wavy; styles 0.6-2.3 mm; pistillate flowering branchlets 0-20 mm; largest medial blades slightly to highly glossy adaxially, margins slightly revolute; Alaska to n California.		77 Salix hookeriana (in part)
41 (28)	Pistillate nectaries usually shorter than or equal to stipes		(42)
+	Pistillate nectaries as long as or longer than stipes		(47)
42 (41)	Largest medial blades amphistomatous.		89 Salix tyrrellii (in part)
+	Largest medial blades usually hypostomatous (or hemiamphistomatous)		(43)
43 (42)	Stipes 0.3-0.8 mm.		88 Salix planifolia (in part)
+	Stipes 0.8-2.7 mm		[2e4. Salix sect. Cinerella].
44	Largest medial blades with revolute margins		(45)
+	Largest medial blades with flat margins		(46)
45 (44)	Shrubs, 0.3-3 m, forming clones by layering; juvenile blades tomentose to glabrescent; anthers 0.4-0.6 mm; ovaries sparsely to moderately densely short-silky.		78 Salix humilis (in part)
+	Shrubs or trees, 3-10(-20) m, not clonal; juvenile blades villous or silky; anthers 0.7-1.2 mm; ovaries very densely long-silky.		79 Salix scouleriana (in part)
46 (44)	Ovaries short-silky, hairs straight; stipes 1.6-2.7 mm; primarily e North America to c British Columbia.		76 Salix discolor (in part)
+	Ovaries villous, tomentose, or woolly, hairs wavy; stipes 0.5-2.2 mm; Alaska to n California.		77 Salix hookeriana (in part)
47 (41)	Floral bracts tawny or light rose; styles 0.4-0.8 mm; stigmas 0.16-0.24 mm; ovaries squat, flask-shaped.		110 Salix breweri (in part)
+	Floral bracts brown or black; styles 0.5-2.3 mm; stigmas 0.2-1.28 mm; ovaries obturbinate, obclavate, or pyriform		(48)
48 (47)	Ovaries long- or short-silky, hairs straight		(49)
+	Ovaries tomentose, villous, or woolly, hairs wavy		(51)
49 (48)	Largest medial blades 29-54 mm wide; branchlets and petioles velvety; branches highly brittle at base.		111 Salix delnortensis (in part)
+	Largest medial blades 5-28 mm wide; branchlets and petioles glabrous, pilose, puberulent, villous, or short-silky; branches flexible at base		[2e6. Salix sect. Phylicifoliae (in part)].
50	Stipules usually marcescent, foliaceous, linear or lanceolate, 2-9.8-23 mm; juvenile blades glabrous or pilose; largest medial blades narrowly elliptic, elliptic, or obovate.		87 Salix pulchra
+	Stipules sometimes marcescent, rudimentary or foliaceous, ovate, oblong, or narrowly elliptic, 1-2.5(-4.5) mm; juvenile blades glabrous, puberulent, pubescent, or densely long-silky; largest medial blades narrowly oblong, narrowly elliptic, elliptic, or oblanceolate.		88 Salix planifolia (in part)
51 (48)	Largest medial blades: abaxial surface glaucous or sparsely to moderately densely hairy, hairs white, sometimes also ferruginous, slightly or highly glossy adaxially; stipes 0.5-2.2 mm; branches highly brittle at base.		77 Salix hookeriana (in part)
+	Largest medial blades: abaxial surface very densely hairy, hairs white, dull or slightly glossy adaxially; stipes 0-0.6 mm; branches flexible at base		(52)
52 (51)	Stipules resinous; floral bracts 2.8-5.2 mm; largest medial blades slightly glossy adaxially, margins flat; petioles weakly ventricose around floral buds.		97 Salix barrattiana
+	Stipules not resinous; floral bracts 1.5-3 mm; largest medial blades dull adaxially, margins revolute; petioles strongly ventricose around floral buds		(53)
53 (52)	Largest medial blades: abaxial surface villous to tomentose, adaxially sparsely to moderately densely hairy; floral bracts: apex often acute to convex, sometimes crenate; stipules sometimes marcescent.		95 Salix alaxensis
+	Largest medial blades: abaxial surface tomentose to woolly, adaxially moderately to very densely hairy; floral bracts: apex convex to rounded, entire; stipules deciduous (in autumn).		96 Salix silicicola
54 (12)	Ovaries hairy.		(55)
+	Ovaries glabrous		[Salix sects. 2e1. Hastatae and 2e2. Cordatae (in part)].
55 (54)	Plants east of 102d meridian (longitudal line passing through the ne corner of Saskatchewan, along e border of Colorado)		(56)
+	Plants west of 102d meridian (longitudal line passing through the ne corner of Saskatchewan, along e border of Colorado)		(62)
56 (55)	Stipules on late leaves usually foliaceous		(57)
+	Stipules on late leaves usually absent or rudimentary		(59)
57 (56)	Branchlets, petioles adaxially, abaxial surface of largest medial blade densely woolly or tomentose; ovaries tomentose or woolly.		91 Salix candida (in part)
+	Branchlets, petioles adaxially, abaxial surface of largest medial blade glabrous, puberulent, villous, or long-silky; ovaries short-silky		(58)
58 (57)	Largest medial blades: margins flat, entire, crenate, or irregularly serrate, adaxial surface dull or slightly glossy; ovaries obclavate; floral bracts 1.2-3.2 mm; stipes 2-6 mm.		84 Salix bebbiana (in part)
+	Largest medial blades: margins slightly revolute, serrulate, adaxial surface slightly or highly glossy; ovaries pyriform; floral bracts 0.8-1.2 mm; stipes 0.6-0.9 mm.		90 Salix arbusculoides (in part)
59 (56)	Largest medial blades: abaxial surface short-silky, hairs usually white (rarely ferruginous); branches highly brittle at base; floral bracts brown to black; ovaries ovoid; styles 0.2-0.4 mm; stipes 0.6-1.5 mm.		107 Salix sericea
+	Largest medial blades: abaxial surface long-silky, villous, pilose, or pubescent to glabrescent, hairs white, often with some ferruginous; branches flexible at base; floral bracts tawny to brown; ovaries pyriform or obclavate; styles 0-0.9 mm; stipes 1-6 mm		(60)
60 (59)	Shrubs delicate, 0.2-1 m; largest medial blades with strongly revolute margins; pistillate catkins densely flowered; capsules 2-4 mm; styles 0.4-0.9 mm; floral bracts 0.7-1.2 mm.		100 Salix argyrocarpa
+	Shrubs coarse, 0.5-10 m; largest medial blades with flat or slightly revolute margins; pistillate catkins loosely flowered; capsules 5-9 mm; styles 0-0.5 mm; floral bracts 1-3.2 mm		(61)
61 (60)	Largest medial blades 1.7-3.9 times as long as wide, narrowly oblong to obovate, hairs white or gray, margins crenate or entire, adaxial surface finely impressed-reticulate; floral bracts tawny; ovaries obclavate.		84 Salix bebbiana (in part)
+	Largest medial blades 5-9 times as long as wide, lorate to very narrowly elliptic, hairs white, sometimes also ferruginous, margins serrulate, serrate, or entire, adaxial surface not finely impressed-reticulate; floral bracts brown, tawny, light rose or bicolor; ovaries pyriform.		101 Salix petiolaris (in part)
62 (55)	Petioles glabrescent or puberulent adaxially		(63)
+	Petioles pubescent, pilose, villous, tomentose, woolly, short-silky, long-silky, or velvety adaxially		(65)
63 (62)	Branchlets glabrous or puberulent; juvenile blades very densely long-silky; stipes 0.6-0.9 mm; pistillate adaxial nectaries equal to or as long as stipes; ovaries very densely short-silky, beaks gradually tapering to styles.		90 Salix arbusculoides (in part)
+	Branchlets pubescent, villous, or velvety; juvenile blades pilose, tomentose, or sparsely or moderately densely long-silky; stipes 1.5-6 mm; pistillate adaxial nectaries shorter than stipes; ovaries densely to sparsely hairy, beaks abruptly tapering to or slightly bulged below styles		(64)
64 (63)	Largest medial blades narrowly oblong, narrowly elliptic, elliptic, oblanceolate, or obovate, 1.7-3.9 times as long as wide, hairs on abaxial surface divergent, wavy; branchlets villous to glabrescent; ovaries obclavate, beaks slightly bulged below styles.		84 Salix bebbiana (in part)
+	Largest medial blades lorate or very narrowly elliptic, 5-9 times as long as wide, hairs on abaxial surface appressed, straight; branchlets pubescent or velvety; ovaries pyriform, beak abruptly tapering to styles.		101 Salix petiolaris (in part)
65 (62)	Largest medial blades not glaucous abaxially		(66)
+	Largest medial blades glaucous abaxially or surfaces obscured by hairs		(67)
66 (65)	Branchlets yellow-green or red-brown, pilose or villous; anthers 0.5-0.9 mm; floral bracts 1.4-2.8 mm; pistillate catkins 11-51 mm.		53 Salix eastwoodiae
+	Branchlets yellowish or yellow-brown, pubescent or long-silky; anthers 0.3-0.5 mm; floral bracts 0.8-2 mm; pistillate catkins 8.5-19 mm.		54 Salix wolfii (in part)
67 (65)	Largest medial blades: abaxial surface densely tomentose or woolly, with crinkled and interwoven hairs, adaxial surface often floccose, hairs white.		91 Salix candida (in part)
+	Largest medial blades: abaxial surface without crinkled, interwoven hairs, adaxial surface not floccose, hairs white or, sometimes, also ferruginous		(68)
68 (67)	Largest medial blades: abaxial surface very densely hairy; peeled wood on branches inconspicuous (sometimes conspicuous in S. geyeriana)		(69)
+	Largest medial blades: abaxial surface sparsely or moderately densely hairy; peeled wood on branches conspicuous		(71)
69 (68)	Largest medial blades 3.6-11.3 times as long as wide, linear, or lorate to very narrowly elliptic; pistillate catkins globose or subglobose; anthers 0.4-0.5 mm; stamens 2.		102 Salix geyeriana (in part)
+	Largest medial blades 2.1-7.7 times as long as wide, lorate, elliptic, narrowly oblanceolate, oblanceolate, or obovate; pistillate catkins slender to stout; anthers 0.5-0.8 mm; stamens 1 or 2		[2e17. Salix sect. Sitchenses (in part)].
70	Largest medial blades 2.1-3.1-4 times as long as wide, margins strongly or slightly revolute, entire or toothed, glands submarginal or epilaminal, abaxial surface woolly, short-silky, or silky-woolly; staminate catkins 22-54 mm, slender or stout; stamens 1; filaments glabrous; pistillate adaxial nectaries square, ovate, or flask-shaped.		108 Salix sitchensis
+	Largest medial blades (2.5-)3.3-5.3-7.3 times as long as wide, margins slightly revolute or flat, entire, glands submarginal, abaxial surface short-silky; staminate catkins 16-16.5 mm, stout or subglobose; stamens 1 or 2; filaments hairy on proximal 1/2; pistillate adaxial nectaries narrowly oblong, oblong, or flask-shaped.		109 Salix jepsonii
71 (68)	Largest medial blades: margins entire, abaxial surface sparsely to moderately densely short- or long-silky, adaxial surface usually dull; filaments hairy basally; anthers purple turning yellow.		55 Salix orestera
+	Largest medial blades: margins crenate, serrate, serrulate, or entire, abaxial surface glabrous, pilose, tomentose, villous, woolly, or short- or long-silky, adaxial surface slightly or highly glossy; filaments glabrous or hairy; anthers yellow or purple turning yellow		(72)
72 (71)	Largest medial blades 1.5-4.2 times as long as wide, 18-63 mm wide, margins entire, irregularly serrate, crenate, or sinuate, adaxial surface pilose, villous, or tomentose; staminate catkins 26-73 mm; pistillate catkins 36-117 mm; styles 0.6-2.3 mm.		77 Salix hookeriana (in part)
+	Largest medial blades 3.4-12 times as long as wide, 5.4-22 mm wide, margins entire or serrulate, adaxial surface silky to glabrescent; staminate catkins 11-28 mm; pistillate catkins 8-44 mm; styles 0.1-1 mm		(73)
73 (72)	Catkins globose to subglobose; floral bracts usually tawny, sometimes brown; anthers 0.4-0.5 mm, yellow or purple turning yellow; styles 0.1-0.6 mm; stipules absent or rudimentary; proximal blades with entire margins.		102 Salix geyeriana (in part)
+	Catkins stout; floral bracts dark brown or bicolor; anthers 0.5-0.9 mm, yellow; styles 0.3-1 mm; stipules foliaceous; proximal blades with entire or serrulate margins.		103 Salix lemmonii
74	Plants east of 102d meridian (longitudal line passing through the ne corner of Saskatchewan, along e border of Colorado)		(75)
+	Plants west of 102d meridian (longitudal line passing through the ne corner of Saskatchewan, along e border of Colorado)		(81)
75 (74)	Largest medial blades not glaucous abaxially		(76)
+	Largest medial blades glaucous abaxially		(78)
76 (75)	Juvenile blades densely villous on abaxial surface or midrib long-silky; largest medial blades usually villous on abaxial surface, hairs white; petioles tomentose adaxially; pistillate adaxial nectaries 0.4-1.3 mm; floral bracts 1-2.6 mm.		52 Salix cordata
+	Juvenile blades glabrous on abaxial surface or midrib sparsely pubescent to short-silky; largest medial blades glabrous or pilose on abaxial surface, hairs white and, sometimes, ferruginous; petioles glabrous, pubescent, or villous adaxially; pistillate adaxial nectaries 0.2-0.4 mm; floral bracts 0.4-1.1 mm		(77)
77 (76)	Shrubs decumbent, 0.1-0.6(-1) m; stipules on late leaves rudimentary to foliaceous, 0.2-1.8(-5) mm; styles 0.3-0.7 mm; proximal blades with crenate margins.		56 Salix myrtillifolia (in part)
+	Shrubs erect, 1-7 m; stipules on late leaves foliaceous, 0.5-6 mm; styles 0.4-1.6 mm; proximal blades with entire or serrulate margins.		57 Salix pseudomyrsinites (in part)
78 (75)	Floral bracts tawny; ovaries obclavate.		62 Salix pyrifolia (in part)
+	Floral bracts usually brown or black; ovaries pyriform		(79)
79 (78)	Largest medial blades 1.4-2.8 times as long as wide, elliptic to obovate, apex usually convex or rounded, sometimes acute; stipules on early leaves absent or rudimentary, on late leaves foliaceous; proximal blades with serrulate or crenulate margins.		58 Salix ballii
+	Largest medial blades 2-8 times as long as wide, usually narrowly oblong, very narrowly elliptic or oblanceolate (sometimes elliptic or obovate), apex acuminate or acute; stipules on all leaves foliaceous; proximal blades with entire or serrulate margins		(80)
80 (79)	Largest medial blades very thickly glaucous abaxially, surface hairs often ferruginous; stigmas 0.24-0.56 mm; pistillate catkins loosely flowered.		67 Salix myricoides (in part)
+	Largest medial blades thinly or moderately glaucous abaxially, surface hairs usually white; stigmas 0.2-0.3 mm; pistillate catkins densely or moderately densely flowered.		68 Salix eriocephala (in part)
81 (74)	Largest medial blades not glaucous abaxially		[Salix sects. 2e1. Hastatae and 2e2. Cordatae (in part)].
+	Largest medial blades glaucous abaxially		(91)
82	Largest medial blades to 60 mm, margins entire, not glandular-dotted; pistillate catkins 8.5-19 mm; stipules deciduous (in autumn); staminate flowers often with abaxial and adaxial nectaries.		54 Salix wolfii (in part)
+	Largest medial blades to 102 mm, margins usually toothed, if entire then also glandular-dotted; pistillate catkins 11-73 mm; stipules often marcescent; staminate flowers without abaxial nectary		(83)
83 (82)	Largest medial blades: surfaces dull adaxially		(84)
+	Largest medial blades: surfaces slightly glossy adaxially		(87)
84 (83)	Branchlets pilose, villous, or woolly		(85)
+	Branchlets glabrous or puberulent		(86)
85 (84)	Juvenile blades tomentose, woolly, or long-silky; largest medial blades 1.5-3.4 times as long as wide, hairs white; pistillate flowering branchlets 3-15 mm; floral bracts: apex rounded to acute.		51 Salix commutata (in part)
+	Juvenile blades villous to pilose; largest medial blades 2-5.2 times as long as wide, hairs usually white and ferruginous; pistillate flowering branchlets 1-9 mm; floral bracts: apex rounded to retuse.		60 Salix boothii (in part)
86 (84)	Juvenile blades pilose to villous abaxially; stigmas slenderly cylindrical, flat, abaxially non-papillate with rounded tip, or 2 plump lobes; styles 0.3-1.4 mm; largest medial blades often amphistomatous.		60 Salix boothii (in part)
+	Juvenile blades glabrous or short- to long-silky abaxially; stigmas broadly cylindrical or flat, non-papillate abaxially, tip rounded; styles 0.2-0.5 mm; largest medial blades hypostomatous.		73 Salix monochroma
87 (83)	Floral bracts 0.4-1.1 mm; pistillate nectaries 0.2-0.4 mm; stipules on early leaves absent, rudimentary, or foliaceous; petioles deeply to shallowly grooved adaxially, usually glabrous		(88)
+	Floral bracts 0.7-3 mm; pistillate nectaries 0.3-1 mm; stipules foliaceous; petioles flat to shallowly grooved adaxially, pilose, tomentose, villous, or pubescent to glabrescent		(89)
88 (87)	Shrubs decumbent, 0.1-0.6(-1) m; stipules on late leaves rudimentary to foliaceous, 0.2-1.8(-5) mm; styles 0.3-0.7 mm; proximal blades with crenate margins.		56 Salix myrtillifolia (in part)
+	Shrubs erect, 1-7 m; stipules on late leaves foliaceous, 0.6-8 mm; styles 0.4-1.6 mm; proximal blades with entire or serrulate margins.		57 Salix pseudomyrsinites (in part)
89 (87)	Juvenile blades tomentose or long-silky; largest medial blades: abaxial surface usually moderately densely tomentose or villous (sometimes pilose to glabrescent), adaxial surface pilose or moderately densely villous to glabrescent; floral bracts tawny, brown, or bicolor; pistillate flowering branchlets 3-30 mm; stipules sometimes marcescent.		51 Salix commutata (in part)
+	Juvenile blades glabrous or pilose; largest medial blades: abaxial surface usually glabrous, pilose, or moderately densely short-silky, adaxial surface pilose or glabrous; floral bracts brown, black, or bicolor; pistillate flowering branchlets 1-10 mm; stipules deciduous (in autumn)		(90)
90 (89)	Largest medial blades 1.6-3.6 times as long as wide, elliptic to broadly so, abaxial surface glabrous or pilose, hairs white; floral bracts: apex acute to convex; stipes 0.2-1 mm.		59 Salix arizonica
+	Largest medial blades 2-5.2 times as long as wide, lorate, narrowly oblong, narrowly elliptic to elliptic or broadly so, abaxial surface pilose to densely short-silky, hairs white, sometimes also ferruginous, sometimes glabrous; floral bracts: apex rounded or retuse; stipes 0.5-2.5 mm.		60 Salix boothii (in part)
91 (81)	Largest medial blades: surfaces slightly or highly glossy adaxially		(92)
+	Largest medial blades dull adaxially		(102)
92 (91)	Floral bracts tawny		(93)
+	Floral bracts brown, black, or bicolor		(95)
93 (92)	Branches red-brown; stipules early deciduous.		62 Salix pyrifolia (in part)
+	Branches yellowish to yellow-brown or gray-brown; stipules deciduous (in autumn)		(94)
94 (93)	Largest medial blades with distinctly toothed margins; pistillate catkins slender to stout; juvenile blades pilose, villous or glabrous.		69 Salix famelica (in part)
+	Largest medial blades with entire or indistinctly toothed margins; pistillate catkins subglobose to stout; juvenile blades long-silky or glabrous.		72 Salix lutea (in part)
95 (92)	Largest medial blades usually with white and ferruginous hairs on midrib of adaxial surface		(96)
+	Largest medial blades with white hairs on midrib of adaxial surface (S. hookeriana may have some ferruginous hairs on surfaces but not restricted to midrib)		(98)
96 (95)	Juvenile leaves reddish; nw California, adjacent Oregon.		106 Salix tracyi (in part)
+	Juvenile leaves yellowish green; Alaska, Alberta, British Columbia, Idaho, Montana, Northwest Territories, Oregon, Wyoming, Yukon		(97)
97 (96)	Largest medial blades narrowly to broadly elliptic, or narrowly ovate to ovate; pistillate nectaries square or obovate; stipules on early leaves foliaceous; branches not glaucous; floral bracts: apex acute or rounded; Alaska, nw Northwest Territories, Yukon.		63 Salix hastata (in part)
+	Largest medial blades narrowly elliptic to elliptic; pistillate nectaries oblong or ovate; stipules on early leaves absent or rudimentary (sometimes foliaceous); branches strongly to weakly glaucous or not; floral bracts: apex rounded; cordillera in Alberta, British Columbia, Idaho, Montana, Oregon, Northwest Territories, Wyoming, Yukon.		64 Salix farriae (in part)
98 (95)	Floral bracts dark brown to black, 1.1-3.6 mm; styles 0.6-2.5 mm; largest medial blades 1.5-4.2 times as long as wide; stigmas usually slenderly or broadly cylindrical, 0.28-0.74 mm; anthers yellow		(99)
+	Floral bracts tawny to light brown, 0.6-1.6 mm; styles 0.1-0.6 mm; largest medial blades 2.6-7 times as long as wide; stigmas flat, abaxially non-papillose, tip round, or 2 plump lobes, 0.12-0.32 mm; anthers purple turning yellow		(100)
99 (98)	Largest medial blades: abaxial surface glabrous or glabrescent, hairs white, margins serrulate, slightly revolute or flat; branches flexible at base.		61 Salix barclayi
+	Largest medial blades: abaxial surface pilose, villous, tomentose, or woolly, hairs often white and ferruginous, margins entire, sinuate to serrulate, or crenate, slightly revolute; branches highly brittle at base.		77 Salix hookeriana (in part)
100 (98)	Branches usually red-brown, sometimes gray-brown (nw California, adjacent Oregon).		106 Salix tracyi (in part)
+	Branches yellowish or grayish		(101)
101 (100)	Largest medial blades with distinctly toothed margins; pistillate catkins slender to stout; juvenile blades pilose, villous, or glabrous.		69 Salix famelica (in part)
+	Largest medial blades with entire or indistinctly toothed margins; pistillate catkins subglobose to stout; juvenile blades long-silky or glabrous.		72 Salix lutea (in part)
102 (91)	Largest medial blades usually with some ferruginous hairs on midrib of adaxial surface		(103)
+	Largest medial blades with white hairs only on midrib of adaxial surface (S. hookeriana may have ferruginous hairs on adaxial surface but not restricted to midrib)		(104)
103 (102)	Largest medial blades narrowly to broadly elliptic or narrowly ovate to ovate; pistillate adaxial nectaries square or obovate; stipules on early leaves foliaceous; branches not glaucous; floral bracts: apex acute or rounded; Alaska, nw Northwest Territories, Yukon.		63 Salix hastata (in part)
+	Largest medial blades narrowly elliptic to elliptic; pistillate adaxial nectaries oblong or ovate; stipules on early leaves absent or rudimentary (sometimes foliaceous); branches strongly to weakly glaucous or not; floral bracts: apex rounded to convex; cordillera in Alberta, British Columbia, Idaho, Montana, Oregon, Wyoming.		64 Salix farriae (in part)
104 (102)	Largest medial blades amphistomatous		(105)
+	Largest medial blades usually hypostomatous, sometimes hemiamphistomatous		(107)
105 (104)	Branches pilose or villous; filaments hairy basally; ovaries: beak slightly bulged below styles.		70 Salix turnorii
+	Branches glabrous; filaments glabrous; ovaries: beak gradually tapering to styles		(106)
106 (105)	Styles 0.6-1.1 mm; juvenile blades villous to long-silky, with white, and sometimes ferruginous, hairs; largest medial blades 2-3.9 times as long as wide, abaxial surface glabrous; stipes 0.5-1.6mm.		66 Salix monticola (in part)
+	Styles 0.13-0.6 mm; juvenile blades glabrous or long-silky, hairs white; largest medial blades 2.8-5.6 times as long as wide, abaxial surface long-silky to pilose or glabrous; stipes 0.9-3.8 mm.		72 Salix lutea (in part)
107 (104)	Largest medial blades slightly glossy adaxially		(108)
+	Largest medial blades dull adaxially		(109)
108 (107)	Largest medial blades with distinctly toothed margins; pistillate catkins slender to stout; juvenile blades pilose, villous, or glabrous.		69 Salix famelica (in part)
+	Largest medial blades with entire or indistinctly toothed margins; pistillate catkins subglobose or stout; juvenile blades long-silky or glabrous.		72 Salix lutea (in part)
109 (107)	Branches yellow-gray, yellow-brown, or gray-brown; floral bracts tawny or brown; ovaries pyriform or ovoid.		72 Salix lutea (in part)
+	Branches usually red-brown, rarely yellow-gray or yellow-brown; floral bracts brown or black; ovaries pyriform		(110)
110 (109)	Styles 0.6-1.1 mm.		66 Salix monticola (in part)
+	Styles 0.2-0.7 mm		(111)
111 (110)	Largest medial blades lorate to narrowly elliptic, 2.9-6.4 times as long as wide, margins usually serrulate or serrate, rarely apparently entire; stipes 0.9-2.5 mm.		71 Salix ligulifolia
+	Largest medial blades narrowly oblong, lanceolate or obovate, 2.4-4.5 times as long as wide, margins prominently serrate, serrulate, or spinulose-serrulate; stipes 1.3-4.2 mm.		74 Salix prolixa