18. Pinus taeda Linnaeus, Sp. Pl. 2: 1000. 1753.
Trees to 46m; trunk to 1.6m diam., usually straight, without adventitious shoots; crown broadly conic to rounded. Bark red-brown, forming square or irregularly rectangular, scaly plates, resin pockets absent. Branches spreading-ascending; twigs moderately slender (to ca. 1cm thick), orangish to yellow-brown, aging darker brown, rough. Buds lance-cylindric, pale red-brown, 1--1.2(--2)cm, mostly less than 1cm broad, slightly resinous; scale margins white-fringed, apex acuminate. Leaves 2--3 per fascicle, ascending to spreading, persisting 3 years, (10--)12--18(--23)cm ´ 1--2mm, straight, slightly twisted, pliant, deep yellow-green, all surfaces with narrow stomatal lines, margins finely serrulate, apex acute to abruptly conic-subulate; sheath 1--2.5cm, base persistent. Pollen cones cylindric, 20--40mm, yellow to yellow-brown. Seed cones maturing in 2 years, shedding seeds soon thereafter, not persistent, solitary or in small clusters, nearly terminal, symmetric, lanceoloid before opening, narrowly ovoid when open, 6--12cm, mostly dull yellow-brown, sessile to nearly sessile, scales without dark border on adaxial surface distally; apophyses dull, slightly thickened, variously raised (more so toward cone base), rhombic, strongly transversely keeled; umbo central, recurved, stoutly pyramidal, tapering to stout-based, sharp prickle. Seeds obdeltoid; body 5--6mm, red-brown; wing to 20mm. 2 n =24.
Mesic lowlands and swamp borders to dry uplands; 0--700m; Ala., Ark., Del., Fla, Ga., Ky., La., Md., Miss., N.J., N.C., Okla., S.C., Tenn., Tex., Va.
Originally most races of Pinus taeda were in the lowlands. Following disturbance of the natural vegetation after settlement by Europeans, the species spread to fine-textured, fallow, upland soils, where it now occurs intermixed with P . echinata and P . virginiana . In the Southeast P . taeda is commonly used in plantation forestry, along with P . elliottii and P . echinata . Pinus taeda frequently forms hybrids with P . echinata and P . palustris ( P . ´ sondereggeri H.H. Chapman). Commercially, it is a valuable pulpwood and timber species.