Study on types composition and distribution characteristics of alien invasive plants in Liaoning

Based on our survey,the species of alien invasive plants are reported in this paper.And the composition,origin area,distribution and pathway of alien invasive plants in Liaoning are discussed.The results show that: ①there are 51 species belonging to 17 families,35genus.There are 11 species in the largest family Compositae.②There are 29 species from America and 10 species from Europe.The harm of the invasive plants from the America is heavier than those from other areas.③43 species are distributed over Dalian areas and 40 species distributed over Shenyang areas.④30 species of the alien invasive plants in Liaoning are intentional introduction,and 15 species are unintentional introduction.