Botanically, poplar belongs to willow. There are three genera in the undergraduate course, namely: Populus, Salix and Salix. Populus euphratica is divided into five factions: Populus euphratica, Populus euphratica, Populus cathayensis, Populus nigra and Populus macrophylla. & lt 1) There are two kinds of Populus euphratica: Populus euphratica and Populus euphratica. Among them, Populus euphratica has natural forests from East Asia to South Europe and Africa. In China, the Tarim River in Xinjiang has the largest distribution area on both sides of rivers in Inner Mongolia and Xinjiang. Populus davidiana is also distributed in the middle and upper reaches of Tarim River. These two varieties have strong drought resistance and salt tolerance. 2) Poplar pie 1. Yang yashan school. Populus davidiana is distributed in Tianshan Mountain and Altai Mountain in China, as well as in Europe, West Asia and North Africa. A variety of Populus davidiana, which is the most widely distributed in China, is Populus davidiana in China. There are big-toothed poplars in North America and southern Canada. Mountain Yang Ya Sect is endemic to China: Populus hopeiensis, distributed in mountainous areas of North China and Northwest China; Populus davidiana is concentrated in the middle and lower reaches of the Yangtze River. It is also distributed in North China, Southeast China and Southwest China.

& ltP>2. Baiyang Ya School; Populus tomentosa is distributed in Europe, Asia and Africa, and there is a natural forest of Populus tomentosa in the Irtysh River basin in Altai, Xinjiang. Populus deltoides is a variety of Populus deltoides, which can be easily introduced to Shaanxi, Gansu, Ningxia and Inner Mongolia. Populus tomentosa is a unique tree species in China, distributed in the middle and lower reaches of the Yellow River.

& ltP & gt(3) Populus deltoides; There are not many natural varieties in this school, but the economic value and genetic value are extremely high. At present, more than 90% of artificially cultivated poplar varieties in the world come from Populus deltoides. There are two major species in this group, namely Populus deltoides distributed in Eurasia and Populus deltoides distributed in North America. There are two main varieties of the former: Populus deltoides (or Populus deltoides) and Populus deltoides. Populus nigra has natural forests in Altai region of China. There are three subspecies of Populus deltoides: Populus deltoides, Populus deltoides and Populus deltoides. There is also a small species of Afghan poplar, which is distributed in Xinjiang and Central Asian countries. Populus deltoides and Populus deltoides, a series of natural and artificial hybrids, are collectively called Populus deltoides. & ltBR & gt& ltBR & gt(4) Qingyang School

& ltP & gt(5) Populus euphratica; Populus euphratica is distributed in Hubei, Sichuan, Shaanxi and Yunnan, with the largest number in western Hubei and eastern Sichuan. Populus tomentosa is produced in Sichuan, Yunnan, Tibet, India and Bhutan. Populus tomentosa grows in Bomi, Tibet. & lt/TD & gt；