Abstract: Salicaceae consists of 650 species in the world and is divided into 3 genera, Chosenia Nakai, Papulus L. and Salix L. The pendulous catkin is favourable to wind pollination and the erect catkin is favourable to insect pollination. The genus Chosenia has staminate catkins that fa-vourable to wind pollination and pistillate catkins that favourable to insect pollination. This kind of structure of the genus Chosenia is an incomplete evolution phenomenon. So, Chosenia is the most primitive genus of the family. Populus is branch of wind pollination and Salix is an other branch of insect pollination. Most species of the family is distributed in north hemisphere. It is a typical temperate family. The centre of its modern distribution and diversity is in east Asia. The place of origin of the family is in the northeast part of East Asia. According to the data of histori-cal geology and fossils, and modern distributon of the family and its outer group, the date of the origin of the family's two branches (wind pollination and insect pollination) is got late in the Aptian of Early Cretaceous, and the ancestors before the origin of the two braocfces maybe pressent before Early Cretaceous.

Key words: Salicaceae