蚬木Excentrodendron hsienmu (Chun et How) H. T. Chang et R. H. Miau

别名：菱叶蚬木;节花蚬木;

科名：椴树科 Tiliaceae

属名：蚬木属 Excentrodendron

《中国植物志》第49(1)卷115页
  1.蚬木 图版29: 1-9
  Excentrodendron hsienmu (Chun et How) H. T. Chang et R. H. Miau in Acta Sci. Nat. Univ. Sunyatsen. 3: 23. 1978.——Burretiodendron hsienmu Chun et How in Acta Phytotax. Sin. 5: 9. 1956;中国高等植物图鉴2: 805. 图3339. 1972.
  常绿乔木，高20米；嫩枝及顶芽无毛。叶革质，卵圆形或椭圆状卵形，长8-14厘米，宽5-8厘米，先端渐尖或尾状渐尖，基部圆形，上面绿色，发亮，脉腋有囊状腺体，下面黄褐色，除脉腋有毛丛外其余秃净，基出脉3条，两条侧脉上升过半，离边缘有1-1.5厘米，有第二次分枝小脉4-5条，另两条边脉靠近叶缘，全缘；叶柄长3.5-6.5厘米。圆锥花序长5-9厘米，有花7-13朵；花柄无节，有短柔毛；两性花：萼片长圆形，长约1厘米，外面被褐色星状柔毛，内面无毛，无腺体，或内侧数片每片有2个球形腺体，花瓣阔倒卵形，长8-9毫米，宽5-6毫米，基部有明显的柄；雄蕊26-35枚，花丝线形，长4-6毫米，基部略连生，花药长3毫米；子房5室，每室有胚珠2颗，生于中轴胎座，花柱5条，极短。雌花未见。翅果长2-3厘米，有5条薄翅。
  产广西。生长于石灰岩的常绿林里，是桂西石灰岩山地常绿林的主要建群种，属珍贵木材。最大的胸径达3米宽。模式标本采自广西龙津县。

《Flora of China》 Vol. 12 (2007)
Excentrodendron tonkinense  (A. Chevalier) Hung T. Chang & R. H. Miao
蚬木   xian mu
Pentace tonkinensis A. Chevalier, Bull. écon, Indochine, n.s., 20: 803. 1918; Burretiodendron hsienmu Chun & F. C. How; B. tonkinense (A. Chevalier) Kostermans; Excentrodendron hsienmu (Chun & F. C. How) Hung T. Chang & R. H. Miao; E. rhombifolium Hung T. Chang & R. H. Miao.
Trees to 40 m. Petiole 3.5-6.5(-10) cm; leaf blade green, orbicular-ovate or elliptic-ovate, 8-14(-18) × 5-8(-12) cm, leathery, glossy, abaxially yellow-brown fascicled hairy in vein axils, lateral basal veins to 1/2 as long as blade, 10-15 mm from margin, each with 4 or 5 secondary veins, base rounded, apex acuminate or caudate-acuminate. Male inflorescences paniculate, 7-13-flowered, 5-9 cm; female inflorescences racemelike, 1-3-flowered. Flowers unisexual. Pedicel not articulate. Sepals oblong-lanceolate, 1-1.5 cm, abaxially brown stellate puberulent, adaxially glabrous, without glands or a few inner petals with 2 globose glands. Petals broadly obovate to spatulate, 8-9 × 5-6 mm, base obviously clawed. Stamens 25-35; filaments 4-6 mm; anthers ca. 3 mm. Female flowers unknown. Capsule
ellipsoid, 2-3 cm.
Evergreen forests on limestone. Guangxi, SE Yunnan [Vietnam].
Excentrodendron tonkinense (as Burretiodendron hsienmu) is included in the IUCN Red List as "Vulnerable (B1+2c)." The wood is very hard and is prized for making chopping boards.