@ARTICLE{TreeBASE2Ref15906, author = {Larry Hufford and Michelle M. McMahon}, title = {Morphological evolution and systematics of Synthyris and Besseya (Veronicaceae): A phylogenetic analysis.}, year = {2004}, keywords = {}, doi = {}, url = {}, pmid = {}, journal = {Systematic Botany}, volume = {}, number = {}, pages = {}, abstract = {Phylogenetic analyses were used to examine the morphological diversity and systematics of Synthyris and Besseya. Strong support was found for the monophyly of Synthyris and Besseya among Veronicaceae in parsimony analyses that applied DNA sequences from the nuclear ribosomal ITS regions. Parsimony and maximum likelihood (ML) criteria provided consistent hypotheses of clades of Synthyris and Besseya based on the ITS data. The combination of morphological characters and ITS data helped to resolve additional clades of Synthyris and Besseya. The results show that Synthyris is paraphyletic to Besseya. In the monophyletic Synthyris clade, Besseya forms part of a Northwest clade that also includes the alpine dissected leaf clade (S. canbyi, S. dissecta, and S. lanuginosa) and mesic forest S. cordata, S. reniformis, S. platycarpa, and S. schizantha. The Northwest clade is the sister of S. borealis, which is disjunct in unglaciated regions of Alaska and Yukon. An Intermountain clade, consisting of S. ranunculina, S. laciniata, S. pinnatifida, and S. missurica, was the sister to the rest of the Synthyris clade. We designed constraint topologies based on prior hypotheses of relationships and morphological similarities and applied these in ML analyses. Parametric bootstrapping was used to compare the likelihood values of the best trees obtained in searches under constraints to that of the best tree found without constraints. These results indicate that topologies in which a monophyletic Synthyris is the sister of Besseya are significantly worse than the best ML tree in which Synthyris is paraphyletic to Besseya. The parametric bootstrap results also indicate that forcing either the monophyly of all taxa that have deeply incised leaf margins or those that have reniform laminas and broadly rounded apices results in trees that are significantly worse than the best ML tree, in which leaf margin incision and reniform laminas are homoplastic. We propose a new classification for Synthyris that emphasizes monophyletic groups. The new combination Synthyris oblongifolia (Pennell) Hufford & McMahon is proposed.} }

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