18. Pinus ponderosa Douglas ex C. Lawson, Agric. Man. 354. 1836.
西黄松 xi huang song
Trees to 70 m tall; trunk to 2.5 m d.b.h. in native range; bark yellow- to red-brown, deeply and irregularly furrowed into broadly oblong, scaly plates; crown broadly conical to rounded; branchlets orange-brown, aging darker, stout, rough; winter buds red-brown, ovoid, very resinous, scales white fringed at margin. Needles tufted at apex of branchlets, spreading to erect, (2 or)3(-5) per bundle, deep yellow-green, slightly twisted, 7-25(-30) cm × (1-)1.2-2 mm, pliant, stomatal lines present on all surfaces, base with persistent sheath 1.5-3 cm, margin serrulate. Seed cones solitary or rarely paired, sessile or subsessile, mostly reddish brown, broadly ovoid when open, symmetric or asymmetric, 5-15 cm, maturing in 2 years, then soon shedding seeds, leaving rosettes of scales on branchlets. Apophyses dull or lustrous, thickened, variously raised, cross keeled; umbo usually pyramidal or truncate, rarely depressed or with a reflexed prickle. Seeds brown or yellow-brown, often mottled darker, ellipsoid-obovoid, 3-9 mm; wing 1.5-2.5 cm.
Cultivated. Henan (Jigong Shan), Jiangsu (Nanjing Shi), Jiangxi (Lu Shan), Liaoning [native to W North America]
This species is economically important and is grown for its fine timber.