Evolutionary relationships within the Lysimachia complex : with special emphasis on Anagallis

Detta är en avhandling från Stockholm : Botaniska institutionen

Sammanfattning: This thesis focuses on Anagallis, an herbaceous genus with a distribution mainly in (sub-) tropical Africa, Madagascar or South America. A few species are found in drier climate. Anagallis is considered close to Lysimachia, separated based on mode of capsule dehiscence. Monophyly of Anagallis was tested by phylogenetic analyses of nuclear and chloroplast DNA sequence data. Character evolution within Anagallis s.l., also including Asterolinon, Pelletiera and Lysimachia nemorum and L. serpyllifolia, was traced by combining morphological and molecular data. With additional chloroplast DNA data, the previously proposed close relationship between Anagallis arvensis and A. foemina was challenged, and the biogeography of “tropical Anagallis” investigated. Both parsimony and Bayesian inference analyses show Anagallis to be non-monophyletic and nested within Lysimachia. A few Anagallis species group together with two Lysimachia species, Asterolinon, and Pelletiera in one clade, whereas all other Anagallis species group in another clade. Morphological synapomorphies of the Anagallis arvensis–Pelletiera clade are few, while the second, strictly Anagallis, clade is recognized by several morphological synapomorphies. Molecular analyses show Anagallis foemina as closer related to A. monelli than to A. arvensis, and the view of A. foemina as a subspecies of A. arvensis should be abandoned. Biogeographic analyses suggest the ancestor of “tropical Anagallis”, i.e. the strictly Anagallis clade, to have had a European distribution. Dispersal to (sub-) tropical Africa has occurred once, while two parallel dispersals from African mainland to Madagascar are suggested. Dispersal from Europe to South America may be explained through long distance dispersal over water, or via land connections. As a concluding part of the thesis, Anagallis, Asterolinon, Pelletiera, and Glaux are merged with Lysimachia based on the results of analyses of molecular and morphological data.

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