Cypselar morphology of Carduus L. (Asteraceae) taxa in Turkey and its taxonomic implications

Abstract Cypselar morphology of 24 taxa including 16 species and eight subspecies of the 29 Turkish Carduus L. (Asteraceae) taxa (belonging to 17 species) were examined by stereomicroscope and scanning electron microscope. In this study, nine qualitative characters (cypselar shape, symmetry, kurtosis, surface ornamentation and different features of cypselar surface cells) and five quantitative characters (cypselar length and width, umbo length and width, ring diameter) were examined. Macromorphological studies revealed oblanceolate, narrowly obovate, narrowly oblong to oblong cypselar shapes with striate or furrowed surface. Based on scanning electron microscopic investigation of cypselar surface, the studied taxa were divided into five main types: scalariform, scalariform-ribbed, scrobiculate-ribbed, scrobiculate and scrobiculate-foveolate. An identification key of studied species based on cypselar morphology has been provided. The results indicate that cypselar features can be used as diagnostic taxonomic characters in examined Carduus species.