Vernonieae (Asteraceae): a palynotaxonomy update to Madagascar and Tropical Africa

Higor Antonio-Domingues 1, Benoit Loeuille 1, Mihajamalala Andotiana Andriamanohera 2, Isabel Larridon 1, Morgan Gostel 3, Ana Rita G. Simões 1

Royal Botanic Gardens, Kew, Richmond, Surrey, UK 1, Botanical Research Institute of Texas, Texas, USA; Royal Botanic Gardens, Kew, Richmond, Surrey, UK 2, Botanical Research Institute of Texas, Texas, USA 3

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 (Vernonia s.s.), urging the reclassification of ca. 1,000 species out of Vernonia. Much of this work has been completed in the Tropical America, but few studies have been undertaken for the more than 700 species of Vernonieae in the in Madagascar, Tropical Africa and Tropical Asia, including the 564 species in Tropical Africa and Madagascar. At least 226 African species remain in Vernonia, but because of poor generic delimitation in this tribe, it is unclear to which genus they belong. We have performed the most complete palynotaxonomy study of Malagasy and Tropical Africa representatives of the tribe Pollen grains and micromorphological reproductive characters were analysed under light microscopy and SEM. Our results demonstrate the eurypalynous status of tribe Vernonieae tribe based on variations in pollen grain size, aperture and ultrasculpture types. Novelties regarding the number and position of the apertures, presence of the operculum and details of the exine ultrasculpture were documented. 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.

Main author career stage: Postdoc / Fellow

Contribution type: Talk

First choice session: 1. Systematics, phylogenetics, biogeography and evolution

Second choice session: 4. Structure, physiology, and development