Trees evergreen, monoecious; branchlets strongly dimorphic: long branchlets growing several cm each year and bearing very slow-growing, lateral short branchlets; winter buds small, scales persistent. Leaves spirally arranged and radially spreading on long branchlets, shorter and very densely clustered on short branchlets, needlelike, triangular or ± quadrangular in cross section, stiff, stomatal lines present both adaxially and abaxially, most numerous abaxially, vascular bundles 2, almost fused, resin canals 2, small, marginal. Cones borne on apex of short branchlets, solitary, erect. Pollen cones with many spirally arranged microsporophylls; microsporangia 2; pollen not saccate. Seed cones erect, light purple at fertilization, maturing in 2nd(or 3rd) year; ovulate scales spirally arranged, sessile, with small bracts and 2 ovules adaxially. Seed scales closely arranged, large, woody, those at base and apex of cone sterile, deciduous at maturity. Bracts minute, falling together with seed scales at maturity from persistent, central axis. Seeds with large, membranous wing. Cotyledons usually 6-10. Germination epigeal. 2n = 24.