Salix subg. Salix

Shrubs or trees, 1–25 m, usually not clonal, or clonal by stem fragmentation. Stems usually erect (pendulous in S. babylonica); branches flexible to highly brittle at base, not glaucous, (usually slightly or highly glossy). Buds alba-type, scale margins connate. Leaves: stipules on early ones usually absent or rudimentary, sometimes foliaceous, on late ones rudimentary or foliaceous, (deciduous spring or autumn); petiole convex, flat, or shallowly to deeply grooved adaxially, not glandular, or with spherical or foliaceous glands distally or throughout; largest medial blade amphistomatous, hemiamphistomatous, or hypostomatous, lorate, narrowly oblong, narrowly elliptic, elliptic, lanceolate, narrowly ovate, or oblanceolate, 2–14.4 times as long as wide, angle of base and of apex less than 90o, surface hairs white and/or ferruginous; juvenile blade hairs white and/or ferruginous. Catkins flowering as leaves emerge (sometimes before in S. babylonica), from lateral buds; staminate on flowering branchlet or sessile, usually slender or stout, sometimes subglobose; pistillate on flowering branchlet, densely or loosely flowered, slender, stout, or subglobose; floral bract usually tawny, sometimes greenish, apex usually entire, toothed, or erose, rarely sinuate; pistillate bract deciduous or persistent after flowering. Staminate flowers: abaxial nectary usually present; stamens 2–10; filaments distinct or connate less than 1/2 their lengths, hairy on proximal 1/2 or basally, rarely glabrous; anthers usually yellow, sometimes reddish turning yellow. Pistillate flowers: abaxial nectary absent or present; ovary not glaucous, glabrous or, rarely, villous, beak usually gradually tapering to styles; ovules 2–36 per ovary; styles connate or distinct; stigmas usually flat, abaxially non-papillate, tip rounded, sometimes stigmas cylindrical, or 2 plump lobes.

Distribution

North America, Mexico, South America, Eurasia.

Discussion

Species 85 (9 species in the flora).

Five of the eight sections recognized in this subgenus are found in the flora area.

See 2a. Salix subg. Protitea for the rationale for including the multistaminate species of sect. Salicaster in subg. Salix.

Selected References

None.

Lower Taxa

Salix sect. Maccallianae, Salix sect. Salicaster, Salix sect. Salix, Salix sect. Subalbae, Salix sect. Triandrae

Key

1	Trees; stems pendulous; pistillate bracts persistent after flowering; pistillate adaxial nectaries longer than stipes; styles 0.15-0.3 mm; stipes 0-0.2 mm; ovules 2-8 per ovary; capsules 1-3.5 mm; stamens 2	Salix sect. Subalbae
1	Shrubs or trees; stems erect; pistillate bracts deciduous after flowering (persistent in S. maccalliana, sometimes persistent until fruiting in S. triandra); pistillate adaxial nectaries shorter than or equal to stipes; styles 0.1-1.2 mm; stipes 0.2-4 mm; ovules 8-30 per ovary; capsules 3.5-12 mm; stamens 2-10	> 5
2	Branches yellowish, yellow-green, or yellow-brown	×sepulcralis
2	Branches yellow-brown to red-brown or gray-brown	> 3
3	Pistillate catkins on flowering branchlets (0-)2-4 mm; ovaries: beak abruptly tapering to styles; anthers 0.4-0.5 mm.	Salix babylonica
3	Pistillate catkins on flowering branchlets 3-14 mm; ovaries: beak gradually tapering to styles; anthers 0.5-0.8 mm	> 4
4	Petioles short-silky adaxially; branches yellowish, yellow-green, or yellow-brown; staminate catkins moderately densely flowered, slender, nectaries distinct	×sepulcralis
4	Petioles glabrous, pilose, or velvety to glabrescent adaxially; branches yellow-brown, gray-brown, or red-brown; staminate catkins loosely flowered, stout, nectaries connate and shallowly cup-shaped	×pendulina
5	Petioles without spherical glands or lobes distally; stamens 2; anthers purple turning yellow in age; ovaries densely villous; pistillate bracts persistent after flowering; leaf blades: abaxial surface not glaucous [2b4. Salix sect. Maccallianae].	Salix maccalliana
5	Petioles with spherical glands or lobes distally; stamens 2 or 3-10; anthers yellow; ovaries glabrous; pistillate bracts deciduous after flowering (sometimes persistent in S. triandra); leaf blades: abaxial surface glaucous or not	> 6
6	Largest medial blades: abaxial surface usually not glaucous; stamens 3-10	Salix sect. Salicaster, 2b5. Salix sect. Triandrae
6	Largest medial blades: abaxial surface glaucous (except usually not glaucous in S. triandra); stamens 2 or 3-6	> 11
7	Largest medial blades: adaxial surface dull or ± slightly glossy; styles 0.2-0.3 mm.	Salix triandra
7	Largest medial blades: adaxial surface slightly or highly glossy; styles 0.3-1 mm	> 8
8	Stipules on early leaves foliaceous; juvenile blade hairs white and ferruginous; branchlets usually hairy, sometimes glabrescent.	Salix lucida
8	Stipules on early leaves absent or rudimentary; juvenile blades glabrous; branchlets glabrous	> 9
9	Largest medial blade margins crenate or crenulate; stamens 2; floral bracts 0.8-1.3 mm; capsules 3-5 mm.	Salix euxina
9	Largest medial blade margins serrulate; stamens 3-10; floral bracts 1.2-4 mm; capsules 6-12 mm	> 10
10	Branches highly glossy; pistillate catkins slender to stout; floral bracts sparsely hairy proximally; ovaries: beak gradually tapering to styles.	Salix pentandra
10	Branches dull or slightly glossy; pistillate catkins stout to globose; floral bracts moderately densely hairy; ovaries: beak slightly bulged below or abruptly tapering to styles.	Salix serissima
11	Juvenile and largest medial blades with white hairs; stamens 2	Salix sect. Salix
11	Juvenile and largest medial blades with white and ferruginous hairs; stamens usually more than 2	Salix sect. Salicaster
12	Largest medial blades persistently silky on both surfaces; petioles long- silky adaxially; styles 0.2-0.4 mm; branches flexible to ± brittle at base.	Salix alba
12	Largest medial blades glabrescent or glabrous on both surfaces; petioles glabrous or puberulent adaxially; styles 0.4-1 mm; branches highly brittle at base	×fragilis
13	Petioles convex to shallowly grooved adaxially; leaf blades: abaxial surface long-silky to glabrescent; stipes 0.3-0.6 mm; pistillate flowering branchlets 8-16 mm	×jesupii
13	Petioles deeply grooved adaxially; leaf blades: abaxial surface usually glabrous or pubescent; stipes 0.8-2 mm; pistillate flowering branchlets 6-56 mm	> 14
14	Stipules: apex convex or rounded; petioles: margins not touching; stamens 3-5.	Salix lasiandra
14	Stipules: apex acuminate or acute; petioles: margins covering groove; stamens 3.	Salix triandra