Ann. Mus. Imp. Fis. Firenze n.s. 1: 181. [preprint p. 29]. 1864.
Trees to 50 m; trunk to 3 m diam. Bark reddish-brown, 10–20 (–25) cm thick, divided into broad, rounded ridges. Branchlet sprays predominantly pinnate. Leaves of branchlets mostly 2–3 mm, apex acute to acuminate, facial leaves frequently separated by paired bases of lateral leaves; glands usually present, linear. Pollen cones 2–4 mm, dark-brown; pollen-sacs red. Seed-cones maturing and opening first-year, 8–12 mm broad, glaucous, purplish to reddish-brown, not notably resinous; scales 5–9. Seeds 2–4 per scale, 2–5 mm, wing equal to or broader than body. 2n = 22.
Habitat: Forests of the Coast Ranges with isolated inland populations at higher elevations in the Siskiyou Mountains and on Mt. Shasta
Elevation: 0–1500 m
A. J. Rehder (1949) listed, with bibliographic citations, 66 published varieties and forms best considered as cultivars.