杜仲(Eucommia ulmoides Oliv),又名木绵、思仲、丝棉木,是我国特有树木。传说古代有个名叫杜仲的人因服此树而得道,故名。又因其皮折之白丝相连,亦称木绵。全世界只此一种,主要分布于长江流域以南各省,山东、河南及陕西、甘肃南部亦有分布。落叶乔木,高可达20米,胸径达1米,树冠圆球型。小枝光滑,具片状髓。叶椭圆状卵形,长7～14厘米,有锯齿,老叶表面网脉下陷,呈皱纹状。翅果狭椭圆形,扁平,顶端2裂。枝、叶、果及树皮断裂后有弹性丝相连。杜仲喜光不耐阴,喜温湿气候,有相当强的耐寒性。由于其根系浅而侧根发达,要求土壤肥沃、湿润、深厚而排水良好,怕粘忌涝。pH值5～7.5时最为适宜,有一 Eucommia ulmoides Oliv, also known as wood cotton, think of Zhong, silk cotton, is unique to our tree. Legend has it that ancient people named Eucommia due to take this tree and Tao, hence the name. Because of its skin-fold white silk connected, also known as wood cotton. Only one in the world, mainly distributed in the provinces south of the Yangtze River, Shandong, Henan and Shaanxi, southern Gansu also have distribution. Deciduous trees, up to 20 meters high, breast diameter of 1 meters, spherical crown. Branchlets smooth, with flaky marrow. Leaves oval-shaped oval, 7 to 14 cm long, serrate, old leaf surface reticulate veins, was wrinkled. Samara narrowly elliptic, flat, 2-lobed apical. Branches, leaves, fruits and bark after the break elastic silk connected. Eucommia light intolerance Yin, hi temperature and humidity, there is a very strong cold tolerance. Because of its shallow roots and lateral roots developed, requires fertile soil, moist, deep and well drained, afraid of sticky waterlogging. The most suitable pH value of 5 to 7.5, there is one