Sp. Pl. 2: 994. 1753.
Trees, deciduous, to 30 m. Bark dark gray and smooth, becoming darker and irregularly fissured with age, inner bark light orange. Twigs reddish brown, 1-2 mm diam., glabrous. Terminal buds chestnut brown, ovoid, 2-4 mm, apex acute, glabrous. Leaves: petiole 2-4(-6) mm, glabrous, rarely sparsely hairy. Leaf blade linear to narrowly elliptic, usually widest near middle, 50-120 × 10-25 mm, base acute, margins entire with 1 apical awn, apex acute; surfaces abaxially pale green, glabrous, rarely softly pubescent, adaxially light green, glabrous. Acorns biennial; cup shallowly saucer-shaped, 3-6.5 mm high × 7.5-11 mm wide, covering 1/4-1/3 nut, outer surface puberulent, inner surface light brown, pubescent, scale tips tightly appressed, acute; nut ovoid to hemispheric, 8-12 × 6.5-10 mm, often striate, glabrate, scar diam. 4.5-6 mm.
Phenology: Flowering spring.
Habitat: Of bottomland flood plains, also on stream banks, dunes, and terraces, and, occasionally, on poorly drained uplands
Elevation: 0-400 m
Ala., Ark., Del., D.C., Fla., Ga., Ill., Ky., La., Md., Miss., Mo., N.J., N.Y., N.C., Okla., Pa., S.C., Tenn., Tex., Va.
Individual trees with leaves softly pubescent abaxially may be classified as Quercus phellos forma intonsa Fernald; however, such leaves are known to occur on second-flush shoots from twigs bearing typical leaves.
Quercus phellos reportedly hybridizes with Q. coccinea (W. W. Ashe 1894); with Q. ilicifolia (= Q. ×giffordi Trelease) and Q. incana (E. J. Palmer 1948); and with Q. marilandica, Q. nigra, Q. pagoda (= Q. ×ludoviciana Sargent), Q. palustris, Q. rubra, Q. shumardii, and Q. velutina. D. M. Hunt (1989) cited evidence of hybridization also with Q. hemisphaerica, Q. imbricaria, Q. laurifolia, and Q. pumila.