Trees (rarely shrubs). Branchlets terete or rhombic in cross section, in fan-shaped or pinnately flattened sprays. Leaves opposite in 4 ranks. Adult leaves usually appressed, lateral and facial pairs similar, closely overlapping, scalelike, free portion of long-shoot leaves to ca. 7 mm; abaxial glands present or absent, circular to linear. Pollen cones with 2–3 pairs of sporophylls, each sporophyll with 2–4 pollen sacs. Seed cones maturing and opening in 1–2 years, nearly globose, glaucous, 4–12 mm; scales persistent, 2–5(–6) pairs, valvate, peltate or basifixed, thick and woody, terminal pair often fused. Seeds 1–4 per cone scale, lenticular, equally 2-winged; cotyledons 2–3. x = 11.
North America, e Asia.
Two Japanese species are widely cultivated and may become established locally. Chamaecyparis obtusa (Siebold & Zuccarini) Endlicher (hinoki-cypress) has obtuse, glandless leaves and seed cones ca. 10–12 mm broad; C. pisifera (Siebold & Zuccarini) Endlicher (sawara-cypress) has acuminate, obscurely glandular leaves and seed cones 6–8 mm broad. Cultivated juvenile forms of several species have been referred to by the superfluous Retinospora Siebold & Zuccarini. Some authors include species of Chamaecyparis in the genus Cupressus.
Species 6–7 (3 in the flora).
|1||Seed cones 4-9 mm broad; leaves usually with circular abaxial glands; Atlantic and Gulf coasts.||Chamaecyparis thyoides|
|1||Seed cones 8-12 mm broad; leaves with linear to circular abaxial glands or glands absent; Pacific Coast.||> 2|
|2||Seed cones with 5-9 scales, opening at end of first year, not notably resinous; leaves usually with linear glands; facial leaves of branchlets frequently separated from each other by paired bases of lateral leaves.||Chamaecyparis lawsoniana|
|2||Seed cones with 4-6 scales, sometimes remaining closed at end of first year, becoming resinous; leaves usually without glands, these circular when present; apices of facial leaves of branchlets often overlapping the base of next facial leaf.||Chamaecyparis nootkatensis|