10. Tilia tuan Szyszyłowicz, Hooker’s Icon. Pl. 20: t. 1926. 1890.
椴树 duan shu
Trees 10-20 m tall. Bark gray, longitudinally exfoliate; branchlets glabrous or tomentose; terminal bud glabrous or hairy. Petiole 1-6 cm, glabrous or tomentose; leaf blade narrowly ovate or ovate-oblong to ovate-orbicular, 6.5-17 × 3.5-11 cm, abaxially glabrous to densely shortly gray-white or brown tomentose, adaxially glabrous, lateral veins 3-11 pairs, base oblique, rounded, truncate, or cordate, margin entire or with a few minute teeth near apex or prominently dentate, apex acuminate or acute. Cymes 3-22-flowered, 5-14 cm, glabrous or hairy. Bracts band-shaped to oblanceolate, 6-16 × 1-3 cm, adnate to peduncle for ca. 1/2 of length, stellate pilose or tomentose to glabrous, base cuneate to rounded, apex obtuse to acuminate, sessile or stalk 0.5-0.8 cm. Pedicel 4-9 mm, glabrous or tomentose. Sepals ovate to ovate-lanceolate, 4-6 mm, abaxially puberulent, adaxially villous at base, margin densely hairy. Petals 6-8 mm, glabrous, shortly clawed. Stamens 35-50, in 5 fascicles, glabrous; staminodes 5, oblanceolate, prominently keeled. Ovary ovoid, densely gray-white stellate tomentose; style 3-4 mm, glabrous. Fruit globose or obovoid-globose, not ridged, 7-11 × 7-9 mm, brown or gray hairy, verrucose; exocarp woody, hard, indehiscent. Fl. Jun-Jul, fr. Jul-Nov. n = 82*.
● Forests; 1200-2400 m. Guangxi, Guizhou, Hubei, Hunan, Jiangsu, Jiangxi, Sichuan, Yunnan, Zhejiang.
Tilia tuan has long been recognized as the most variable Tilia within China (e.g., by Rehder and Wilson in Sargent, Pl. Wilson. 2: 368. 1915). Pigott (Edinburgh J. Bot. 59: 239-246. 2002) indicated that he believes that a number of the more local species in China should be included within T. tuan, a view that has been at least partially followed in this account.