Deciduous trees and shrubs, with wood of light weight. Tree trunks 1 or 2-4 together, often leaning; shrubs often clumpy and sometimes forming thickets by the growth of underground runners. Twigs mostly slender but sometimes stoutish (S. discolor, S. caprea), terete. Bark on young twigs usually smooth; green, yellow, brown, purplish, or black, sometimes shining; glabrous, glabrate, puberulent, gray-pubescent, or white-tomentose, varying with species, age of twigs, and season. Pith small, round, continuous, white. Buds small to large, 1-2 mm. to 10 mm. or more long, oblong to ovate, appressed, solitary (or sometimes multiple), with a single exposed scale, colored and clothed as the twigs; terminal bud lacking. Leaf-scars alternate or rarely sub-opposite or opposite (S. purpurea), shallow, narrow, curved; bundle-traces 3. Stipule-scars tiny to obvious, sometimes absent. Aments of precocious species sometimes appearing in February or March.
Fig. 28. Salix nigra.
a. Trees, twigs mostly slender, yellow-ish to brown or black;buds small to midsized (except S. fragilis), 1-5 mm.long
b. Twigs not markedly pendulous (weeping)
c. Twigs yellow or yellowish, glabrous
c. Twigs yellowish or greenish (seasonal) to dark brown or black; native trees
d. Small tree or shrub; bark gray; twigs not brittle; buds small, 1-3 mm. long
d. Large tree;bark dark brown to black; twigs brittle at base;buds small to midsized, 2-5 mm. long, reddish brown.
Text contributed by Carleton R. Ball
c. Twigs greenish-yellow (young) to reddish-brown (older);introduced trees
d. Bark gray, thick, rough; twigs very brittle at base; buds midsized to large, 3-7 (-10) mm. long
d. Bark gray-brown, rough, ridged ;twigs not brittle; buds small to midsized,1-3 (-5) mm. long
b. Twigs long, pendulous (weeping)
Shrubs, or occasionally small trees (as also is S. caroliniana above)
b. Buds alternate
c. Thicket-forming, stoloni-ferous shrub, 2-3m. high; twigs slender; buds small, 2-4 mm. long
c. Not thicket-forming or stoloniferous shrubs
d. Buds small to midsized, 2-6 or rarely 7 mm. long (4-7 (-10) mm. in S. discolor)
e. Older twigs and buds glabrous (except in hairy varieties, as noted)
f. Twigs midsized to stout, 2-6 (-7) mm. wide at base
g. Seasonal twigs yellowish-brown,
older reddish-brown or darker, shining, not clearly furrowed, the larger somewhat grayish at base
h. Bark brown, twigs longish (hairy in var. intonsa)
S. lucid a
h. Bark olive-green, shining, twigs shorter
g. Seasonal twigs yellowish-brown, older dark brown or blackish, shallowly straight-furrowed, some partly shining, many short and divaricate
Twigs mostly slender to occasionally midsized, 1-4 (-5)mm.wide at base
g. Bark gray; twigs slender, leafy, young yellowish and occasionally puberulent, older dark brown or reddish-brown, glabrous, seldom shining
g. Bark brown;twigs slender or sometimes midsized, longish, young yellowish-brown to dark brown, puberulent, older dark brown to black, glabrous or sometimes micro-puberulent (plants with older twigs pubescent probably represent S. subsericea)
Twigs stoutish, reddish or reddish-purple to
mostly dark brown, youngest thinly pubescent (more densely so in var. latifolia), older glabrous; buds large, 4-7 (-l0)mm. long
Twigs and buds more or less hairy, not shining.
f. Tall shrubs to 5 or 6 m. high; twigs and buds mostly midsizec
g. Bark brown; twigs slender to midsized, longish, 2-5 mm. in basal diameter, yellow to yellowish-brown
10. S. rigida
g. Bark brown; twigs midsized to stout-ish, 2-5 (-7)mm. in basal diameter, short to long, yellow or yellowish-brown to dark brown(densely white-tomentose on the common var. albovestita, with buds to 8 mm. long)
f. Shrub or small tree, 2 to 6 (-9)m. high; bark grayish, rough, scaly; twigs 1-3 (-4) mm. at base, reddish to dark brown, often divaricate, the shorter often crooked;buds mid sized
f. Low, many-stemmed shrub to 1 m.high; twigs slender, 1-3 mm
in diameter; yellowish-brown to brown; buds small 1-3 (-4)mm. long
d. Buds midsized to large, 4-8 (-10)mm. long, pubescent
e. Introduced shrub or small tree, bark gray; 1-2 year twigs yellowish, older dark brown, stoutish
e. Native shrubs or small trees; bark brown;twigs mostly reddish-brown to dark brown
f. Few-stemmed shrub or small tree, 2-7 m. high; bark brown;young-er twigs often pubescent (more densely so in var latifolia), older glabrous stoutish
f. Sprangly shrub 1-3 m. high; bark brown; twigs midsized, pubescent, younger yellowish
Buds opposite, subopposite, or alternate (on same twig), midsized to large, 3-8(-9)mm. long, glabrous (introduced shrub)
1. S. lucida Muhl. Shining Willow. Shrub or small tree 3-6 (-9)m. high, the trunk to 1. 2 dm. in diameter; bark brown, glabrous; twigs mostly midsized (2-5 mm. in diameter), chestnut-brown to reddish-brown or darker, glabrous or young twigs more or less hairy (var. intonsa Fernald); buds midsized, 4-6 mm. long, colored and clothed as the twigs; leaf-scars lunate; bundle-traces conspicuous. Low grounds, Delaware to Iowa and North Dakota, north to Newfoundland and west to Manitoba.
2. S. serissima (Bailey) Fernald. Autumn Willow. Shrub 1-4 m. high, branches with olive-brown, lustrous bark, twigs slender, yellowish-brown to brown, shining, glabrous; buds missized, lance-oblong, 5-7 mm. long, chestnut-brown to olive or reddish-brown, glabrous, shining. Swampy and boggy ground, rather than along streams, from New Jersey to Ohio and Indiana, Minnesota, Montana, north to Newfoundland, James Bay, Saskatchewan, and Alberta.
3. S. carotiniana Michx. Carolina Willow. Ward's Willow. Shrub or small tree to 19 m. high in our area, larger westward; bark gray, deeply checkered; twigs slender, the seasonal 0.5-1 mm., older to 4 mm. in diameter, yellowish, becoming brown to black with age, the youngest pubescent to glabrous; buds very small, 1-3 mm. long, colored and clothed as the twigs. Stream banks and low woods, Florida, Texas, north to Maryland, Pennsylvania, Illinois and Kansas: also in Cuba.
4. S. amygdaloides Anders son. Peachleaf Willow. Shrub or small tree with 1-3 often leaning trunks to 12 m. high and to 4 dm. in diameter; bark brown, scaly or fissured; twigs slender, 1-3 mm. in diameter, yellow, glabrous; buds small, 2-4 mm. long, yellow or yellowish-brown. Alluvial soils, usually near water, Pennsylvania to Texas and Arizona, north to Quebec and British Columbia.
5. S. nigra Marsh. Black Willow. A shrub or tree to 30 m. high, with 1-4 often leaning trunks to 5 dm. in diameter, the largest of the native willows; bark flaky, dark brown to black; twigs slender, 1-3 mm. in diameter, greenish to dark brown, glabrescent, somewhat brittle at base; buds small, 2-4mm. long,red-dish-brown. Abundant in alluvial soils along streams and in low. woods, Florida to Texas, north to New Brunswick, Nebraska, and Minnesota (Fig. 28).
6. S. fragilis L. Brittle Willow. Crack Willow. English Willow. Tree to 20 or 25 m. high, sometimes with 2 or 3 trunks, 1-2 m. in diameter; bark thick, rough, gray; twigs slender, greenish-yellow to reddish-brown, pubescent to glabrous, somewhat lustrous, very brittle at base (hence the Latin and English names); buds midsized, 3-7 mm. or occasionally 10 mm. long, brown. Widely introduced from Europe in colonial days, for sentiment and for charcoal to use in making gunpowder; sparingly escaped along watercourses near towns and farmsteads. Extensively hybridized with S. alba both in Europe and America.
7. 3. alba L. White Willow. Cricket-bat Willow. Large tree to 20 m. or more in height, and to 1 m. or more in diameter, often with two or three large trunks above the base; bark rough, coarsely ridged, gray to brownish; seasonal twigs greenish-yellow, pubescent; older twigs reddish-brown, glabrous; buds very small, 1-3 (-5) mm. long, colored as twigs. Var. vitellina (L.) Koch has young twigs yellow, but is very rare in America where most of the collection so named really are hybrids of S. fragilis and S. alba. Widely introduced from Europe in early days for ornament, basketry, poles, charcoal for making gunpowder and medicinal uses; escaped to a considerable extent in some places.
8. S. babylonica L. Weeping Willow. A tree to 12 m. or more high and 1 m. in diameter; bark grayish-brown; twigs very slender, elongated, pendulous, the younger yellow, gradually becoming brownish to brown, tough, puberulent to glabrous; buds small, 1-4 mm. long, yellowish to brown, late-developing. Widely introduced from Europe, especially for cemeteries and as an ornamental, sparingly escaped. Not native to the Babylon area but the Latin name sentimentally based on Psalm 137 because long grown in Europe as a "mourning tree".
9. S. interior Rowlee. Sandbar Willow. Longleaf Willow. A thicket-forming, stoloniferous shrub 2-5 m. high; stems 3-6 or rarely 10 cm. in diameter; bark grayish; twigs slender, red or reddish-brown, glabrescent-glabrous; buds small, 2-4 mm. long, late in developing. Common on alluvial soils, mudbars, sandbars, and beaches. Pennsylvania, Virginia, West Virginia, and Kentucky, thence south to Louisiana and Texas, west to the western edge of the Great Plains in the United States and southern Canada, and northwest to James Bay, Mackenzie, Yukon and Alaska.