Systematics/Phytogeography / Taxonomie/ Section
Sinou, Carole , Bruneau, Anne , Forest, Felix L. , Lewis, Gwilym P. .
Phylogeny of the genus Bauhinia (Leguminosae: Caesalpinioideae: Cercideae).
The pantropical genus Bauhinia s.l., comprises approximately 330 species, and is a morphologically and ecologically highly variable grade in the tribe Cercideae, one of the first branching lineages in the Leguminosae. As the largest genus in this tribe, Bauhinia is key to a better global understanding of the evolution of the family. Numerous regional taxonomic treatments and partial phylogenies have been published, often leading to taxonomic ambiguities. Recently the genus Bauhinia s.l. has been subdivided into eight genera: Bauhinia s.s., Gigasiphon, Barklya, Piliostigma, Tylosema, Lysiphyllum, Lasiobema and Phanera. Preliminary phylogenetic analyses of sequences from the plastid trnL-F region partly support this taxonomic division. To further assess taxonomic delimitations among these segregates and phylogenetic relationships within Cercideae, we analysed plastid sequences from the matK regions for 90 species of Bauhinia s.l., including all of the generic segregates. Our analyses also include a broad sampling of the four other Cercideae genera. Parsimony and Bayesian analyses indicate that Bauhinia s.l., including the monospecific Breneria, consisted of two sister lineages. The first one comprises the African genus Piliostigma, the pantropical Bauhinia s.s. and the African Brenierea. Sister to this clade, the second lineage comprises the mostly African genus Gigasiphon followed by the African genus Tylosema, and a trichotomy that comprises the Australian Barklya, the American species of Phanera and a clade consisting of the Asian species of Phanera, the Asian Lasiobema and Australian Lysiphyllum. Our results suggest that Phanera may be paraphyletic as it includes species of Lasiobema. Within Cercideae, the genus Cercis occurs as sister to the remaining genera, and Adenolobus is sister to the clade that includes Griffonia and Bauhinia s.l. These results are concordant with the recently proposed phylogeny of the genus, except for the placement of Piliostigma in a clade with Bauhinia s.s. and Brenierea.
Log in to add this item to your schedule
1 - Université de Montréal, Institut de Recherche en Biologie Végétale, 4101 Sherbrooke est, Montréal, Québec, H1X 2B2, Canada
2 - Université de Montréal, Institut de recherche en biologie végétale, 4101 rue Sherbrooke est, Montréal, Québec, H1X 2B2, Canada
3 - Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, England
4 - Royal Botanic Gardens, Kew, Herbarium, Richmond, Surrey, TW9 3AB, England
trnL-F and matK sequences
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM