Cytology and embryology of the pompom weed, Campuloclinium macrocephalum (Eupatorieae, Asteraceae)

► Campuloclinium macrocephalum is a common weed introduced to South Africa. ► We carried out a meiotic and embryological analysis to understand the reproductive system of the species. ► The results revealed five triploid (2n = 3x = 30) and one diploid (2n = 2x = 20) populations. ► The triploid specimens have embryo sac development from a nucellar cell (apospory), which indicates that they are apomictics. ► The aposporous apomixis could be responsible for the invasiveness of C. macrocephalum.