Agrostidoideous Flora(Agrostidoideae) on the Coastal Region of Hainan Island

The Agrostidoideous flora on the coastal region of Hainan Island consists of 140 species in 82 genera.It is conspicuous for tropical elements.The tropical areal-types of genera take up 94.6% of the total ones.In the total genera,pantropics,old world tropics,tropical Asia to tropical Africa takes up 47.30%,16.22% and 13.51%,respectively.In the level of species the tropical elements accounts for 78.9% of the total with the tropical Asia ones accounting for 35.16%,the old world tropics for 14.84%,the tropical Asia to tropical Australasia ones for 12.50%,and the pantropics for 11.72%.The flora has a lot of monodominant species or dominant species in the coastal communities.The relationships of the Agrostidoideous flora between the coastal region of Hainan with its vicinity are analysed.Concise assessment on the Agrostidoideous resources in the coastal region of Hainan is presented in the paper.