Systematics Section / ASPT
Sinou, Carole , Bruneau, Anne , Forest, Felix L. , Lewis, Gwilym P. .
Phylogenetic analysis of the genus Bauhinia (Leguminosae: Caesalpinioideae: Cercideae).
The pantropical genus Bauhinia s.l. comprises approximately 350 species and exhibits an impressive amount of morphological and ecological variation. As the largest genus in Cercideae, the tribe sister to the rest of the Leguminosae, Bauhinia is key to a better global understanding of the evolution of the family. To date, only regional taxonomic treatments and partial phylogenies have been published, often leading to taxonomic ambiguities. Recently the genus Bauhinia s.l. once again has been subdivided, this time into eight genera: Bauhinia s.s., Gigasiphon, Barklya, Piliostigma, Tylosema, Lysiphyllum, Lasiobema and Phanera. To examine taxonomic delimitations among these segregates and to assess phylogenetic relationships within Cercideae, we analysed plastid sequences from the trnL-F region for 80 species of Bauhinia s.l., including all generic segregates, and matK sequences for a subset of taxa. Our analyses also include a broad sampling of the four other Cercideae genera. Parsimony and Bayesian analyses indicate that the genus Bauhinia s.l. can be considered monophyletic only if it includes the monospecific Brenierea. In addition, our results suggest that the generic segregate Phanera may be paraphyletic as it includes species of Lasiobema. The other six generic segregates are supported as monophyletic. The first lineage of Bauhinia s.l. comprises the American and African Bauhinia s.s + Brenierea clade, followed by the mostly African Gigasiphon and Tylosema clades, the Australian Barklya, and a primarily Asian clade that includes a trichotomy with Lysiphyllum, Piliostigma and the Phanera-Lasiobema lineage. Within Cercideae, the north temperate genus Cercis occurs as sister to the remaining genera. The next lineages to diverge are the southern African Adenolobus, followed by the west and central African genus Griffonia sister to Bauhinia s.l. These analyses support the recently proposed classification for Bauhinia s.l. as well as biogeographic hypotheses that suggest the Leguminosae may have diverged from drier temperate elements.
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: Oral Paper:Papers for Sections
Location: Stevens 3/Hilton
Date: Wednesday, July 11th, 2007
Time: 3:15 PM