Ph.d.-forsvar Gustavo Hassemer – Københavns Universitet

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Ph.d.-forsvar Gustavo Hassemer

Phylogenetic, taxonomic and biogeographic studies of the genus Plantago (Plantaginaceae).

Plantago, a cosmopolitan group of mostly herbaceous plants distributed all over the world including over 250 species, is a genus of difficult taxonomy, mainly because of its reduced morphology, which features relatively few characters for species classification and identification. This thesis includes research that advances the phylogenetic, taxonomic and biogeographic knowledge of the genus Plantago. Field observations and an extensive revision of herbarium collections and taxonomic literature were used to describe three new species, P. hatschbachiana, P. humboldtiana and P. nebularis, and propose a new name, P. zoellneriana, two new combinations, P. napiformis and P. pretoana, 13 synonymisations, 12 revalidations and 23 typifications. Additionally, many species had their distribution and conservation status assessed or updated. Furthermore, the most comprehensive molecular phylogenetic investigation of Plantago subgenus Plantago to date is presented, applying modern high-throughput sequencing techniques of the plastome as well as the nuclear encoded ITS regions. Cytonuclear discordance is observed, but is attributed mainly to lack of resolution in the ITS region. This improved phylogenetic knowledge was applied to support the proposal of a new sectional classification of Plantago subgenus Plantago, and based on the phylogenetic results one new section, Plantago sect. Pacifica, was created. The results of this thesis highlight the importance of applying both morphological studies and state-of-the-art high-throughput DNA data to resolve outstanding taxonomic puzzles exemplified by the plant genus Plantago.

Principal Supervisor

  • Professor Nina Rønsted (Natural History Museum, Denmark).

Co-supervisors

  • Dr. Heidi Meudt, Museum of New Zealand Te Papa Tongarewa.
  • Dr. Chris Barnes, Natural History Museum of Denmark.

Assessment Committee

  • Associate Professor Nina Lundholm (Section for EvoGenomics, Natural History Museum, Denmark) – chairman
  • Professor Dirk Albach, Department of Biology and Environmental Sciences, Director of the Botanical Garden.Carl von Ossietzky Universität Oldenburg.
  • Senior Researcher Daniela Zappi, Instituto Tecnológico Vale, Belém, Pará, Brasil.