New Pollen Morphological Perspectives into Vernonia (Compositae—Vernonieae) from Madagascar

A comprehensive palynotaxonomic study is presented of species of Vernonia from Madagascar, documenting 37 (out of 44) taxa using light microscopy (LM) and scanning electron microscopy (SEM). Statistical analyses were performed to explore patterns of variation in quantitative data between the species. The pollen variation is categorised into two pollen types based on qualitative and quantitative characters, which was supported by Principal Components Analysis. A mesoaperture, a unique apertural structure, is also described for the genus for the first time. Further integrative taxonomic studies focused on Vernonia and the Vernonieae tribe, including species from continental Africa and Madagascar, are ongoing and will help to determine whether these characters remain taxonomically informative and whether they could be applied in an evolutionary framework.