论文部分内容阅读
垂榆(Ulmus pumila var.pendulaRehd.)为白榆的变种。落叶乔木,树体粗壮,寿命长。树冠成伞形或蘑菇形,树形美,侧枝多,细弱、下垂,垂枝可长达2～4m。树皮灰色或暗灰色,幼龄树皮较平滑,老龄树皮粗糙。叶互生,羽状排列。椭圆状卵形或椭圆状披针形,长2～8cm,宽2～3cm,尖端锐尖或渐尖,叶缘具不规则复锯齿或单锯齿,有光泽。垂榆适应性强,适应范围广,新疆、内蒙古、山东、山西、辽宁、吉林等省(区)均有栽植。并且耐干旱、瘠薄,生长速度
Ulmus pumila var .pendulaRehd. Is a variant of Ulmus pumila. Deciduous trees, thick sturdy trees, long life. Canopy into umbrella or mushroom-shaped, tree-shaped United States, side branches and more, weak, drooping, weeping can be up to 2 ~ 4m. Bark gray or dark gray, young bark smooth, old bark rough. Leaves alternate, plume arrangement. Oval-shaped oval or oval-shaped lanceolate, long 2 ~ 8cm, width 2 ~ 3cm, sharp tip or tapering, leaf margin with irregular serrated or single serrated, shiny. Dendrobium adaptable, adaptable to a wide range of Xinjiang, Inner Mongolia, Shandong, Shanxi, Liaoning, Jilin and other provinces (regions) are planted. And resistant to drought, infertility, growth rate