20. Pinus glabra Walter, Fl. Carol. 237. 1788.
Trees to 30m; trunk to 1m diam., straight; crown conic to rounded. Bark gray, fissured and cross-checked into elongate, irregular, scaly plates, resin pockets absent, on upper sections of trunk ± smooth, gray, looking slick. Branches whorled, spreading to ascending; twigs slender, purple-red to red-brown, occasionally glaucous, aging gray, smooth. Buds ovoid to ovoid-cylindric, red-brown, ca. 0.5--1cm, slightly resinous; scale margins finely fringed. Leaves 2 per fascicle, spreading to ascending, persisting 2--3 years, 4--8(--10)cm ´ 0.7--1.2mm, straight, slightly twisted, dark green, all surfaces with fine stomatal lines, margins finely serrulate, apex sharply conic; sheath 0.5--1cm, base persistent. Pollen cones lance-cylindric, 10--15mm, purple-brown. Seed cones maturing in 2 years, shedding seeds soon thereafter, semipersistent, spreading to recurved, nearly symmetric, lance-ovoid before opening, ovoid-cylindric when open, 3.5--7cm, red-brown, aging gray, nearly sessile or on stalks to 1cm, scales lacking contrasting border on adaxial surfaces (as in P . echinata ); apophyses but slightly thickened and raised; umbo central, depressed, unarmed or with small, curved, weak, deciduous, short-incurved prickle. Seeds deltoid-obovoid; body ca. 6mm, brown, mottled darker; wing to ca. 12mm. 2 n =24.
Sandy alluvium and mesic woodland; 0--150m; Ala., Fla., Ga., La., Miss., S.C.
Pinus glabra is more shade tolerant than most yellow pines. Although the trees grow large, the wood is not much valued. The species is similar in tree form to P . strobus . It resembles P . echinata in shoot and leaf but has less prickly cones and deeper green leaves.