一、北京市园林绿化杨柳树基本情况杨树和柳树为雌雄异株植物,分为雌株与雄株,它们的花为单性花,葇荑花序。当春天杨树还没有长出嫩叶时,雄株上的雄花先开放,经过一段时间发育成熟后,雄花序上的花药自然裂开,花粉飞散而出,进行传粉,然后雄花序逐渐萎蔫脱落,春天在一些杨树的下面看到的像毛毛虫似的那些东西就是杨树的雄花序。比雄花稍晚一些,雌株上的雌花开始开放,伴随着雌花序的发育成熟,雌树上鲜嫩的幼叶也开始慢慢地长出来。雌花序是由若干朵小花组成穗状的葇荑花序,每一朵小花发育后长 First, the basic situation of poplar and willow trees in Beijing City Poplar and willow trees are dioecious plants, divided into female and male plants, their flowers are unisexual flowers, catkin inflorescence. When spring poplar has not grown young leaves, the male flowers on the male plant first open, after a period of maturity, the anthers on the male inflorescence naturally dehiscence, pollen flying out, pollination, and then the male inflorescence wilting gradually fall off The caterpillars that spring saw under poplar trees are the male inflorescences of poplars. A little later than the male flowers, female flowers on the female plant began to open, with the maturity of the female inflorescence, young leaves on the female tree began to grow slowly. Female inflorescence is composed of a number of small flowers spike-like inflorescence inflorescence, each flower after the development of long