Trees evergreen, monoecious; trunk straight; bark reddish brown to dark gray, fibrous, peeling off into long shreds; crown pyramidal or ovoid; branches ± whorled, horizontal or erect-spreading; winter buds small. Leaves persisting 4 or 5 years, spirally 5-ranked, spreading or directed forward, subulate, straight or incurved at apex, adaxial and abaxial surfaces convex, lateral surfaces slightly flattened, keeled, stomatal bands present on all 4 surfaces, base decurrent, apex acute. Pollen cones axillary toward apex of 2nd year branchlets, usually crowded into a short, terminal, sessile, oblong raceme, plum red turning yellow when mature; microsporophylls many, spirally arranged; pollen sacs (3 or)4 or 5(or 6). Seed cones terminal, solitary or occasionally aggregated, nodding, sessile, ± globose, rosettelike and resembling opening buds, ripening in 1st year, persisting 1-2 years longer with branchlet growth often temporarily continuing through cone; bracts and cone scales connate; bracts borne on middle or proximal middle part of abaxial surface of cone scales, triangular, small; ovules 2-5 per bract axil; cone scales persistent, shield-shaped, cuneate, thickened distally, woody, umbo with a central spine and 4 or 5(-7) toothlike projections on distal margin; apical scales small and sterile. Seeds irregularly compressed-ellipsoid or-triangular-ellipsoid, very narrowly winged. Cotyledons (2 or)3(or 4). Germination epigeal. 2n = 22*.
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Medium-sized to large evergreen tree (smaller in many cvs); branches irregularly whorled; bark moderately thick, fibrous, rather hard. Winter buds minute, hidden by immature lvs. Lvs monomorphic, subulate (juvenile lvs) or linear-subulate, laterally compressed and 4-angled, incurved and usually falcate, with stomata on all 4 sides; base adnate and decurrent on shoot. ♂ strobili (cones) axillary from just behind terminal bud, oblong, the many stamens imbricate. ♀ cones terminal, solitary, subglobose, ripening in first year, but persistent after dehiscence. Scales 20-30, woody, enlarged distally; terminal part of bract scale free, broad-triangular; ovuliferous scales with several prominent, spiny processes on upper margin. Seeds 2-5 to each scale, narrowly winged, irregularly shaped, somewhat flattened.
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