Leaf and stem anatomy and micromorphology of four Inuleae (Compositae) genera, with notes on their taxonomic significance

We studied the leaf and stem anatomy and micromorphology of 17 Inula, Dittrichia, Limbarda and Pulicaria taxa native to the Balkan region, aiming to identify additional characters that may help to define the taxa within this group.The taxa analysed were all previously placed in different sections within Inula, but have later been segregated into separate genera. According to the latest molecular phylogenetic analyses, as well as morphological and karyological data, Inula sect. Corvisartia, including the type species of the genus (I. helenium), should be segregated from the remaining Inula species as a separate genus. However, data on the anatomical and micromorphological structure of the vegetative organs of the analyzed taxa have been sparse and incomplete, and previous analyses were carried out on a small number of taxa, with less emphasis on comparisons. We studied more than 50 qualitative and quantitative characters that were analyzed and measured using dissecting, compound and scanning electron microscopes and the data were statistically processed. The results show that certain characters are useful for separating individual taxa, but their grouping does not follow the current taxonomic classification. However, I. helenium is clearly distinguished from the remaining taxa, which supports its separation as a separate genus.