Tall pyramidal trees, with bark containing numerous resin-vesicles, smooth, pale, and thin on young trees, often thick and deeply furrowed in old age, pale and usually brittle wood, slender horizontal wide-spreading branches in regular remote 4 or 5-branched whorls, clothed with twice or thrice forked lateral branches forming flat-topped masses of foliage gradually narrowed from the base to the apex of the branch, the ultimate divisions stout, glabrous or pubescent, and small subglobose or ovoid winter branch-buds usually thickly covered with resin, or in one species large and acute, with thin loosely imbricated scales. Leaves linear, sessile, on young plants and on lower sterile branches flattened and mostly grooved on the upper side, or in one species 4-sided, rounded and usually emarginate at apex, appearing 2-ranked by a twist near their base or occasionally spreading from all sides of the branch, only rarely stomatiferous above, on upper fertile branches and leading shoots usually crowded, more or less erect, often incurved or falcate, thick, convex on the upper side, or quadrangular in some species and then obtuse, or acute at apex and frequently stomatiferous on all sides; persistent usually for eight or ten years, in falling leaving small circular scars. Flowers axillary, from buds formed the previous season on branchlets of the year, surrounded at the base by conspicuous involucres of enlarged bud-scales, the male very abundant on the lower side of branches above the middle of the tree, oval or oblong-cylindric with yellow or scarlet anthers surmounted by short knob-like projections, the female usually on the upper side only of the topmost branches, or in some species scattered also over the upper half of the tree, erect, globose, ovoid or oblong, their scales imbricated in many series, obovate, rounded above, cuneate below, much shorter than their acute or dilated mucronate bracts. Fruit an erect ovoid or oblong-cylindric cone, its scales closely imbricated, thin, incurved at the broad apex and generally narrowed below into long stipes, decreasing in size and sterile toward the ends of the cone, falling at maturity with their bracts and seeds from the stout tapering axis of the cone long-persistent on the branch. Seeds furnished with large conspicuous resin-vesicles, ovoid or oblong, acute at base, covered on the upper side and infolded below on the lower side by the base of their thin wing abruptly enlarged at the oblique apex; seed-coat thin, of 2 layers, the outer thick, coriaceous, the inner membranaceous; cotyledons 4—10, much shorter than the inferior radicle.