Carpological and receptacular morpho-anatomical characters of Inula , Dittrichia, Limbarda and Pulicaria species (Compositae, Inuleae): Taxonomic implications

•Characters of fruit and receptacle, specific to genera and species, are described.•Criteria useful for delimitation of frequently misidentified taxa are provided.•Distribution of fruit sclerenchyma and receptacle features tend to be diagnostic for genera.•Fruit and receptacle morpho-anatomy support segregation of I. helenium into a separate genus.