A taxonomic revision of non-native Cenchrus s.str. (Paniceae, Poaceae) in the Mediterranean area

Abstract

The exact identity of non-native, naturalised populations of Cenchrus s.str. in the Mediterranean area has been critically assessed. A herbarium revision confirmed the presence of three species: Cenchrus echinatus, C. longispinus and C. spinifex (syn.: C. incertus). In the present paper C. echinatus is reported for the first time from Spain and confirmed for Egypt and Israel. C. longispinus, up to present widely confused with C. spinifex, is reported for the first time from Croatia, Greece, Israel and Morocco and furthermore confirmed for France (including Corse) and Italy. Finally, C. spinifex is confirmed for France, Italy and Spain, while records from Greece and Israel proved to be in error for C. longispinus. All three species are much alike and widely confused in the studied area. In some areas (especially in parts of Italy and Israel) two species occur sympatrically, which largely added to the confusion. Main features for their distinction are discussed and a dichotomous key for the identification of the native and non-native species of Cenchrus s.str. in the Mediterranean area is presented. © 2012 BGBM Berlin-Dahlem.