T r e e s  o f  N o r t h  C a r o l i n a

Salix L. (Salicaceae)

A genus of about 400 species, trees, shrubs, and subshrubs, mostly north temperate and boreal.

Twelve arborescent species occur in North Carolina; three are native to the state: S. caroliniana (Carolina willow), S. nigra (Black willow), and S. sericea (Silky willow).

Key to aborescent Salix in North Carolina

1. Bud apex sharp-pointed; bud scale margin free and overlapping; leaf blades 2.5-16× as long as wide; leaf blades (4-) 7.5-9 (-16)× as long as wide...2.

2. Leaves glaucous beneath; pistils borne on stipes averaging 2 mm long (range 1-5 mm); stipules usually prominent and persistent, to 15 mm long; leaf blades (4-) avg. 7.5 (-13)× as long as wide...S. caroliniana (Carolina willow)

2. Leaves not (or thinly) glaucous beneath; pistils borne on stipes averaging 1 mm long (range 0.5-1.5 mm); stipules usually small and caducous, to 12 mm long; leaf blades (4-) avg. 9 (-16)× as long as wide...S. nigra (Black willow)

1. Bud apex blunt; bud scale margin fused; leaf blades 2-30× as long as wide...3.

3. Leaves green or pale green beneath...*S. pentandra (Bay willow)

3. Leaves glaucous beneath...4.

4. Leaf margin crenate or irregularly serrate...5.

5. Leaves glabrate (sparsely pubescent when young), not revolute...*S. discolor (Pussy willow)

5. Leaves permanently pubescent, at least on the lower surface (densely villous or tomentose when young), revolute...6.

6. Trees or tall shrubs, to 15 m tall; decorticated wood of 1-4 year old branches smooth or with a few ridges usually < 5 mm long...*S. caprea (Goat willow)

6. Small trees or shrubs, 3-7 (12) m tall; decorticated wood of 1-4 year old branches with numerous ridges, many of them longer than 2 cm...7.

7. Leaves tomentose beneath with a mixture of white and rusty hairs...*S. atrocinerea (Common sallow)

7. Leaves tomentose beneath with white or gray hairs...*S. cinerea (Gray willow)

4. Leaf margin serrulate or serrate...8.

8. Leaves lacking stomates on upper surface...S. sericea (Silky willow)

8. Leaves exhibiting stomates on upper surface...9.

9. Leaves long-sericeous beneath; branches ascending (rarely pendulous); leaves narrowly lanceolate, with length/width ratio of 5-6.5; petioles 3-6 mm long; petioles 3-6 mm long, sericeous; flowering branchlets 1-1.5 cm long...*S. alba (European white willow)

9. Leaves glabrate beneath; branches normally pendulous; leaves very narrowly lanceolate, with length/width ratio of 6.5-13; petioles 7-12 mm long; petioles 7-12 mm long, tomentose; flowering branchlets ca. 0.3 cm long...10.

10. Branches yellowish, yellow-green, or yellow-brown...*S. × sepulcralis (Weeping willow)

10. Branches yellow-brown to red-brown, or gray-brown...11.

11. Pistillate catkins on branchlets that are (0-) 2-4 mm long; ovary beak abruptly tapered to styles; anthers 0.4-0.5 mm long...*S. babylonica (Weeping willow)

11. Pistillate catkins on branchlets that are 3-14 mm long; ovary beak gradually tapered to styles; anthers 0.5-0.8 mm long...12.

12. Petioles glabrous, pilose, or velvety to glabrescent on the upper surface; branches yellow-brown, gray-brown, or red-brown; staminate catkins loosely flowered, stout, nectaries connate connate and shallowly cup-shaped...*S. × pendulina (Weeping willow)

12. Petioles short-silky on the upper surface; branches yellow-brown; staminate catkins moderately densely flowered. slender, nectaries distinct...*S. × sepulcralis (Weeping willow)