In the framework of collection and determination of coastal sand dune plants of S Caspian Sea in Gilan and Mazandaran provinces (N Iran), a new species of the family Poaceae,Cenchrus longispinus (Hack.) Fernald, was determined in coastline of Babolsar, Mazandaran. Cenchrus longispinus is closely resembles C. spinifex and C. echinatus. From the latter it is best distinguished by the absence of a...