Contribution of definition the relationship among five species of Poa L. (Poaceae) depending on the morphological features and leaf epidermal structure

Five species of the genus Poa L. from (Poaceae) were collected and studied in Lattakia, they are : P. annua ، P.infirma ، P. pratensis ، P. bulbosa ،P. nemoralis. This study put data base of the morphological features which included : habit, leaves, ligule, the structure of the inflorescence , spikelet, floret, micro-morphological characteristics which contained the epidermal structure of abaxial leaf surface, and the difference between costal and inter-costal zones of the 5 species, studying of pollen grain clarified the similarity in shape but there was a simple difference in measurements . Then , data from micro and macro morphological study were used to made a Dendrogram by using Statistica . The dendrogram showed the linkage of two annual species P. annua ، P.infirma in a cluster , every one of three another species had his specific cluster , P. nemoralis was closer to the annual species .