Ambrosia tenuifolia Spreng. (Compositae) is a new addition to the flora of Turkey from Malatya (in the East Anatolia region). The specimens collected from Malatya have different properties from the known diagnostic characteristics of the species. A. tenuifolia is a monoecious plant without glands. Its female capitula are in the axils of the upper leaves in its original description, but some of our specimens have only female capitula (female capitula in terminal racemes and lower parts of the racemes bracteate, but upper parts ebracteate) and there are many glands particularly on the tops of their fruits. The diagnostic characteristics, ecology of the species and important aspects of variation in our specimens are given.

Ambrosia tenuifolia Spreng. (Compositae) is a new addition to the flora of Turkey from Malatya (in the East Anatolia region). The specimens collected from Malatya have different properties from the known diagnostic characteristics of the species. A. tenuifolia is a monoecious plant without glands. Its female capitula are in the axils of the upper leaves in its original description, but some of our specimens have only female capitula (female capitula in terminal racemes and lower parts of the racemes bracteate, but upper parts ebracteate) and there are many glands particularly on the tops of their fruits. The diagnostic characteristics, ecology of the species and important aspects of variation in our specimens are given.