Format: ORAL

Higor Antonio-Domingues1, Benoit Loeuille1, Isabel Larridon1, Morgan Gostel2, Ana Rita G. Simes1

1 Royal Botanic Gardens, Kew, Richmond, Surrey, UK 2 Botanical Research Institute of Texas, Texas, USA

One of the largest tribes in Asteraceae, Vernonieae, has proven intractable for taxonomic revision, with more than 1,000 of the ca. 1,500 species being recognised in the genus Vernonia. This genus has recently been re-circumscribed to include just 21 accepted species in the Americas, prompting the reclassification of ca. 1,000 species out of Vernonia. Much of this work has been completed in the Neotropics, but few studies have been undertaken for the more than 700 species of Vernonieae in the Paleotropics. At least 200 African species remain in Vernonia, but due to poor generic delimitation in this tribe, it is unclear to which genus they belong. We have performed the most complete palynotaxonomy study of Malagasy representatives of the tribe Vernonieae to date, which is represented by 90 species, including 39 still placed in Vernonia. Pollen grains and micromorphological reproductive characters were analysed under light microscopy and SEM. Our results the eurypalynous status of tribe Vernonieae tribe based on variations in pollen grain size, aperture and ultrasculpture types. Further study that includes more comprehensive molecular sampling of species in Vernonieae is in progress and will be elemental for further understanding the diversity and evolution of pollen within this tribe.