Abstract Detail

Systematics Section/ASPT

Sinou, Carole [1], Bruneau, Anne [2].

Multi-locus phylogenetic analysis of the genus Bauhinia s.l. (Cercideae, Leguminosae).

Resolving the phylogeny of the large pantropical genus Bauhinia L. is a quest followed by only a few researchers. The genus in its broadest circumscription includes approximately 350 species of shrubs, lianas and small trees, easily recognised by their usually bilobed leaves and palmate venation. Bauhinia remains one of the large, challenging genera of caesalpinioid legumes in need of a taxonomic revision. Recent phylogenetic analyses have revealed that Bauhinia s.l. is not monophyletic, suggesting that the genus is divided into two lineages and includes the monospecific genus Brenierea Humbert. Here we present phylogenetic analyses for a broad sampling of Bauhinia s.l. and other Cercideae genera based on sequence data from two plastid (trnL-F, matK-trnK) and two nuclear (Leafy, LegCyc) regions. This multi-locus dataset has been a challenge to analyse because of duplication in LegCyc and allelic variation in Leafy, but has nonetheless helped to better resolve the species history of Bauhinia s.l. Despite differences in species-level topologies amongst the loci analysed, Bauhinia s.l. is consistently divided into two lineages, the Phanera and the Bauhinia clades. The Phanera clade includes the monophyletic segregate genera Phanera Lour., Lysiphyllum (Benth.) deWit, Barklya F. Muell., Gigasiphon Drake, and Tylosema (Schweinf.) Torre & Hillc. Phanera itself is divided into two lineages: an Asian one that includes species of the genus Lasiobema (Korth.) Miq., suggesting that the latter should be recognised as a section of Phanera, and an American lineage that can best be described as the genus Schnella Raddi. The Bauhinia clade is composed of the genera Bauhinia s.s., Piliostigma Hochst, and Brenierea. The position of the genus Griffonia Baill. is unstable, occurring either within the Bauhinia clade or as sister to the two large Bauhinia s.l. clades depending on the gene regions analysed. Thus, as noted in some previous taxonomic treatments, the genus Bauhinia s.l. should be divided into eight genera, leaving Bauhinia s.s as a genus of approximately 150 species. Our analyses suggest the occurrence of multiple long-distance dispersal events from Africa to both Asia and America, leading to the current pantropical distribution.

Broader Impacts:

1 - Université de Montréal, Institut de Recherche en Biologie Végétale and Département de Sciences biologiques, 4101 Sherbrooke est, Montréal, QC, H1X 2B2, Canada
2 - University of Montreal, Institut de recherche en biologie végétale, 4101 rue Sherbrooke Est, Montreal, QC, H1X 2B2, Canada

Keywords:
Leguminosae
Phylogenetic analysis
Low-copy nuclear gene
Bauhinia
Caesalpinioideae.

Presentation Type: Oral Paper:Papers for Sections
Session: 5
Location: Rosedown/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 9:45 AM
Number: 5006
Abstract ID:554
Candidate for Awards:None