Pin oak

Trees , deciduous, to 25 m. Bark grayish brown, fissures broad, shallow, inner bark pinkish. Twigs reddish brown, 1.5-3(-4) mm diam., soon becoming glabrous. Terminal buds brown to reddish brown, ovoid, 3-5 mm, glabrous or with a few fine hairs at apex. Leaves: petiole 20-60 mm, glabrous. Leaf blade elliptic to oblong, 50-160 × 50-120 mm, base cuneate to broadly obtuse or truncate with basal pair of lobes often somewhat recurved, margins with 5-7 lobes and 10-30 awns, lobes acute or attenuate or distally expanded, apex acute to acuminate; surfaces abaxially glabrous except for conspicuous axillary tufts of tomentum, veins raised, adaxially planar, glabrous. Acorns biennial; cup thin, saucer-shaped, 3-6 mm high × 9.5-16 mm wide, covering 1/4 nut, outer surface glabrous or puberulent, inner surface glabrous or with a few hairs around scar, scale tips tightly appressed, acute to obtuse; nut globose or ovoid, 10-16 × 9-15 mm, often conspicuously striate, glabrous, scar diam. 5.5-9 mm. 2 n = 24.

Flowering spring. Bottoms and poorly drained upland clay soils; 0-350 m; Ont.; Ark., Conn., Del., D.C., Ill., Ind., Iowa, Kans., Ky., Md., Mass., Mich., Mo., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., Tenn., Va., W.Va., Wis.

Quercus palustris is especially common in landscape and street plantings. Its persistent dead branchlets (pins) and branching pattern (drooping lower branches, horizontal middle branches, ascending upper branches) are quite distinctive.

This species reportedly hybridizes with Quercus coccinea (E. J. Palmer 1948) and with Q . imbricaria (= Q . × exacta Trelease), Q . marilandica , Q . nigra , Q . phellos (= Q . × schochiana Dieck), Q . rubra , Q . shumardii , and Q . velutina .

Some Native American tribes used infusions prepared from the bark of Quercus palustris to alleviate intestinal pains (D. E. Moerman 1986).