紫椴 zi duan

Trees to 25 m tall, 1 m d.b.h. Bark dark gray, exfoliating; branchlets white or reddish stellate pubescent, glabrescent; terminal bud glabrous, bud scales 3. Petiole slender, 2-3.5 cm, glabrous; leaf blade broadly ovate or ovate-orbicular, 4.5-6 × 4-5.5 cm, abaxially greenish, hairy only in vein axils, adaxially glabrous, lateral veins 4-5 pairs, base cordate or rarely obliquely truncate, margin serrate, teeth ca. 1 mm, pointed, apex acute, acuminate, truncate or slightly emarginate or 3-lobed. Cymes 3-20-flowered, slender, 3-5 cm, glabrous. Bracts on 1-3.5 cm stalk, narrowly band-shaped, 3-7 × 0.5-0.8 cm, adnate to peduncle for 1/3-1/2 of length, both surfaces glabrous. Pedicel 7-10 mm. Sepals broadly lanceolate, 5-6 mm, abaxially stellate puberulent. Petals 6-7 mm. Stamens 20, 5-6 mm; staminodes absent. Ovary canescent-tomentose; style ca. 5 mm, glabrous. Fruit ovoid-globose, 5-angled or obscurely angled, 5-8 mm, stellate tomentose; exocarp thickly leathery, fragile, indehiscent. Fl. Jul. 2n = 82.

Mixed Abies and Picea forests; 1300-1400 m. Heilongjiang, Jilin, Liaoning [Korea, Russia].

Tilia amurensis is similar to T. japonica but differs in having smaller leaves and bracts and a shorter cyme.