Description from Flora of China
Thuja orientalis Linnaeus, Sp. Pl. 2: 1002. 1753; Biota orientalis (Linnaeus) Endlicher; Platycladus stricta Spach; Thuja chengii Borderes & Gaussen; T. orientalis var. argyi Lemee & H. Léveillé.
Trees to more than 20 m tall; trunk to 1 m (or more) d.b.h.; bark reddish brown to light grayish brown, thin, flaking in long strips; crown ovoid-pyramidal when young, broadly rounded or irregular when old. Leaves 1-3 mm, apex bluntly pointed; facial leaves rhomboid, with a conspicuous, linear, glandular groove at center abaxially; lateral leaves overlapping facial ones, boat-shaped, ridged, apex slightly incurved. Pollen cones yellowish green, ovoid, 2-3 mm. Seed cones when immature bluish green, subglobose, ca. 3 mm in diam., when ripe reddish brown, subovoid, 1.5-2(-2.5) × 1-1.8 cm; proximal 2 fertile cone scales 2-seeded, distal 2 fertile scales 1-seeded. Seeds grayish brown or purplish brown, ovoid or subellipsoid, 5-7 × 3-4 mm, slightly ridged. Pollination Mar-Apr, seed maturity Oct.
Natural occurrences are difficult to distinguish from local introductions, owing to extensive cultivation and planting in the past; 300-3300 m. Native in S Gansu, Hebei, Henan, Shaanxi,
Shanxi; introduced or status uncertain in Anhui, Fujian, N Guangdong, N Guangxi, Guizhou, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, S Nei Mongol, Shandong, Sichuan, Xizang,
Yunnan, Zhejiang [Korea, E Russia].