Trees to 31m; trunk to 0.9m diam., straight or crooked, commonly with adventitious sprouts; crown rounded or irregular. Bark red-brown, deeply and irregularly furrowed, with long, irregularly rectangular, flat, scaly ridges, resin pockets absent. Branches arching-spreading to ascending, poorly self-pruning; 2-year-old branchlets stout (mostly over 5mm thick), orange-brown, aging darker brown, rough. Buds ovoid to ovoid-cylindric, red-brown, ca. 1--1.5cm, resinous; scale margins fringed, apex cuspidate. Leaves 3(--5) per fascicle, spreading to ascending, persisting 2--3 years, 5--10(--15)cm ´ 1--1.5(--2)mm, straight, twisted, deep to pale yellow-green, all surfaces with fine stomatal lines, margins serrulate, apex abruptly subulate-acuminate; sheath 0.9--1.2cm, base persistent. Pollen cones cylindric, ca. 20mm, yellow. Seed cones maturing in 2 years, shedding seeds soon thereafter or variously serotinous and long-persistent, often clustered, symmetric, conic to ovoid before opening, broadly ovoid with flat or slightly convex base when open, 3--9cm, creamy brown to light red-brown, sessile to short-stalked, base truncate, scales firm, with dark red-brown border on adaxial surface distally; apophyses slightly raised, rhombic, with strong transverse keels; umbo central, low-triangular, with slender, downcurved prickle. Seeds broadly obliquely obovoid-deltoid; body 4--5(--6)mm, dark brown, mottled darker, or near black; wing 15--20mm. 2 n =24. Upland or lowland, sterile, dry to boggy soils; 0--1400m; Ont., Que.; Conn., Del., Ga., Ky., Maine, Md., Mass., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tenn., Vt., Va., W.Va. Pinus rigida often has poor form and is not valued highly as saw timber. It is fire successional, sprouts adventitiously, and is frequently shrubby in the northern part of its range. It is known to hybridize naturally with P . echinata .
Tree 15 - 30 m tall, trunk diameter 0.5 - 1 m Bark: deep reddish brown to dark gray, thick, and deeply furrowed, with broad, scaly ridges exposing brown inner layers. Trunk sometimes growing adventitious tufts of needles. Twigs: green, becoming orangish brown with age. Buds: reddish brown, 1 - 1.5 cm long, egg-shaped, pointed, with fringed scales. Form: irregular or rounded. Pollen cones: yellow, small, cylindrical, and clustered at the tips of branches. Needles: in clusters of three, light green, shiny, 7.5 - 13 cm long, sharp-pointed, twisted, finely toothed, and stout. Young seed cones: light green, small, spherical, and near the tips of branchlets. Pollination between cones occurs in spring. Mature seed cones: woody, nearly stalkless, clustered, light brown to reddish brown, 4 - 8 cm long, and round to egg-shaped with a slightly flattened base. Scales thin, flat, ridged on the outer face and armed with a prickle. Seeds dark brown, mottled, 4 - 6 mm long, and nearly triangular, with wings 6 - 8 mm long. Open cones remain on the tree for many years, long after seed dispersal.
Similar species: Having three-clustered needles is what distinguishes Pinus rigida from all other Pinus species in the Chicago Region, which have either two or five needles per cluster.
Habitat and ecology: Pinus rigida is native to the eastern United States, where it is tolerant of many habitats with sandy to gravelly, often poor soils. In the Chicago Region, it can be found just south of the Dead River at Illinois Beach State Park in Lake County, Illinois, not far from Lake Michigan. It can also be found in a sandy Black Oak savanna near the Tefft Savanna Nature Preserve in Jasper County, where it escaped from a plantation. Very few specimens exist at these locations.
Occurence in the Chicago region: non-native
Notes: The common name for Pinus rigida refers to the resin in its knotty wood, from which the early colonists produced turpentine and tar for axle grease. These knots were also attached to poles and used as torches. Today, the wood is not highly valued, but is used for lumber and pulp.
Etymology: Pinus is the Latin word for pine. Rigida means rigid, and refers to the stiff cone scales and needles.
Tree to 20 m, with spreading, irregular branches; bark dark and very rough; twigs brown; terminal buds ca 1.5 cm, their scales chestnut-brown, fringed, resinous; lvs mostly in 3's, persisting 2-3 years, stiff, dark green, 7-12 cm נca 2 mm; cones divergent, conic-ovoid, 4-7 cm, long-persistent but generally opening at maturity; apophysis thickened and somewhat elevated, the umbo elevated and with a slender spine 1-3 mm; seeds ca 1.5 cm. Dry, rocky or sandy soil; s. Me. to s. Que. and s. Ont., s. to n. Ga., and with outlying stations in c. and w. Ky.; dominant on the pine-barrens of N.J., but seldom on the coastal plain farther south.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.