Trees to 23 m, shrubby where subject to fires; crown conic at first, broadly columnar with age, dense. Bark smooth at first, remaining so or becoming rough, furrowed, fibrous. Branchlets decussate, 1.3--2.3 mm diam. Leaves usually with conspicuous, pitlike, abaxial gland that produces drop of resin, often highly glaucous. Pollen cones 2--5 ยด 2 mm; pollen sacs mostly 4--6. Seed cones globose or oblong, mostly 2--3 cm, gray or brown, often glaucous at first; scales mostly 3--4 pairs, smooth or with scattered resin blisters, sometimes with erect conic umbos to 4 mm, especially on apical scales. Seeds mostly 4--6 mm, light tan to dark brown, not glaucous to heavily glaucous. 2 n = 22. Canyon bottoms, pinyon-juniper woodland, chaparral; 750--2000 m; Ariz., Calif., N.Mex., Tex.; Mexico. Bark texture and foliage features have been used to distinguish geographic varieties or segregate species. Although bark texture may be consistent within populations, over the species as a whole there is complete intergradation between smooth and fibrous barks. Various forms are commonly cultivated and sometimes persistent in the southern United States.