Trees, 5-10 m. Stems: branches ± brittle at base, gray-brown to red-brown, glabrous, villous, or tomentose; branchlets yellow-brown to red-brown, glabrous, sparsely or densely villous or tomentose. Leaves: stipules rudimentary or foliaceous on early ones, foliaceous on late ones, apex convex to acute; petiole (with spherical glands distally), (3-)4.5-14(-22) mm, tomentose or pilose adaxially; largest medial blade lorate or lanceolate to narrowly lanceolate, (50-)75-115(-220) × 10-22(-35) mm, 5-10 times as long as wide, base usually convex or cuneate, sometimes rounded to cordate, margins serrate or serrulate, apex acuminate, acute, or caudate, abaxial surface glabrous or sparsely tomentose on midribs, hairs white and/or ferruginous, wavy, adaxial highly glossy, glabrous or pilose, hairs white and/or ferruginous; proximal blade margins entire or serrulate; juvenile blade glabrous, or moderately densely tomentose or silky abaxially, hairs white and ferruginous. Catkins: staminate 28-97 × 5-11 mm, flowering branchlet 4-25 mm; pistillate 33-93 × 7-15 mm, flowering branchlet 3-35 mm; floral bract 1-3 mm, apex acute or rounded, entire or erose, abaxially sparsely hairy, hairs wavy; pistillate bract deciduous after flowering. Staminate flowers: abaxial nectary 0.3-0.5 mm, adaxial nectary oblong to narrowly oblong, 0.3-0.6 mm, nectaries distinct; stamens 4-7; filaments (sometimes connate less than 1/2 their lengths), hairy basally; anthers 0.4-0.6 mm. Pistillate flowers: adaxial nectary oblong, square, or ovate, 0.3-0.7 mm; stipe 1.3-5.3 mm; ovary pyriform to obclavate, beak slightly bulged below styles; ovules 12-16 per ovary; styles (sometimes distinct distally), 0.1-0.2 mm; stigmas 0.16-0.2-0.28 mm. Capsules 4-6 mm. Flowering (south) Dec-early May, (north) mid Apr-early Jun. Alluvial woods on floodplains, swamps, hummocks, marshes, wet interdunal depressions, rocky or gravelly streambeds, ditches, canals, usually on calcareous substrates; 0-600 m; Ala., Ark., D.C., Fla., Ga., Ill., Ind., Kans., Ky., La., Md., Miss., Mo., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., Va., W.Va.; Mexico (Nuevo León); West Indies (Cuba); Central America (Guatemala). Hybrids:
Salix caroliniana forms natural hybrids with S. nigra. Hybrids with S. amygdaloides have been reported (N. M. Glatfelter 1898); no convincing specimens have been seen.
Salix caroliniana × S. nigra: This hybrid is characterized by stipes to 1.3 mm and leaves glaucous; it probably occurs wherever the two parents come into contact. In the southeastern United States, it occurs from northern Florida to West Virginia and Maryland with intergradation mainly on the Atlantic coastal plain from northern Florida and southern Georgia (G. W. Argus 1986). Reports (N. M. Glatfelter 1898) of it from the vicinity of St. Louis, Missouri, are unconfirmed.
From Flora of Indiana (1940) by Charles C. Deam
This low, sprawling shrub I have found growing in the crevices of large rocks along the bank of the Ohio River about 6 miles above Cannelton, in Perry County, and in crevices of rocks in the overflow bank of Buck Creek, about 6 miles north of Laconia in Harrison County. A shrub about 2 inches in diameter and 6 feet high was found growing between layers of limestone rock, about a foot above the water from a bank about 2 feet high on the north side of Laughery Creek about a fourth mile east of Friendship, Ripley County. Good specimens are difficult to obtain because in all localities the plants are submerged during high water. The shrubs are sprawling in character because debris and ice continually keep them broken off, although they are very tough. This is a southern willow and should be sought all along the Ohio River.
Shrub or tree to 10 m, or larger westward; buds conic, sharp-tipped, the short (3-7 mm) scale with free, overlapping margins; petioles and twigs yellowish to dark brown, usually white-hairy the first year, the petiole with glandular dots or processes at the summit; stipules well developed and persistent, 7-15 mm, broadly reniform, serrulate; lvs spreading, lance-linear to lanceolate (or the young ones often oblanceolate and obtuse), 7-15 נ0.7-3 cm, mostly 5-10 times as long as wide, long-acuminate, closely serrulate, dark green or yellowish-green above, densely glaucous beneath, often hairy, especially along the midrib, the areoles minute beneath; catkins with the lvs, 3-11 cm, on lax, leafy peduncles 2-5(-7) cm; scales yellowish, villous, deciduous; stamens (4-)6(-8); fr narrowly lance-ovate, 3-6 mm, granular-roughened; pedicels 1.5-5 mm; style 0.1-0.2 mm. Floodplains and other moist or wet low places; Del., Md., and the Potomac and Ohio valleys (to Pittsburgh and s. Ind.), w. to e. Kans. and Okla., s. to Cuba and Guat. (S. ambigua; S. longipes; S. wardii)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.