Systematics Section / ASPT
Steele, Kelly P. , Kenicer, Gregory J. , Wojciechowski, Martin F. .
Phylogenetic analyses of genera in the tribes Trifolieae and Fabeae (Leguminosae) using nucleotide sequence data of the plastid gene matK.
Phylogenetic analyses using nucleotide sequences of the plastid gene matK from 84 species from most genera traditionally included in the tribes Trifolieae and Fabeae (syn. Vicieae) support the monophyly of most currently recognized genera except for the genus Vicia. Results also indicate that Trifolium is the sister group to a clade composed of genera in the Fabeae (Vicia, Lens, Pisum, and Lathyrus) rather than being in a clade with other genera in the Trifolieae, the tribe in which Trifolium is traditionally placed. To provide further information on relationships within some larger genera in these two tribes, to include genera not sampled previously (such as Vavilovia), and to test the conclusions of earlier studies, nucleotide sequences of both the adjacent 5’ trnK intron and the matK gene were utilized and approximately 45 species were added to the data set. Results indicate that Vavilovia is sister to Pisum, forming a group that is sister to all species of Lathyrus. Results of these analyses generally support the hypotheses that Vicia is paraphyletic; that Lathyrus, Medicago, and Trifolium are each monophyletic; and that Melilotus is nested within a paraphyletic group of Trigonella species. Increased sampling provides support for the hypothesis that species in Medicago section Buceras form a clade that is sister to the remaining species in the genus. Relationships retrieved for the increased sample set of Lathyrus indicate two major clades within the genus, which reflect ‘oroboid’ and ‘lathyroid’ lineages. Results of phylogenetic analyses are used to consider plausible hypotheses of biogeographic origins and distribution patterns, particularly for species with a primarily north temperate distribution. Hypotheses on the independent origin of trifoliate leaves in Trifolium, Ononis, and the clade comprising Medicago and Trigonella are also considered.
1 - Arizona State University, School of Life Sciences, PO Box 874501, Tempe, Arizona, 85287-4501, USA
2 - Arizona State University East, Department of Applied Biological Sciences, 7001 E. Williams Field Road, Mesa, Arizona, 85212, USA
3 - University of Edinburgh, and Royal Botanic Garden Edinburgh, Institute of Cell and Molecular Biology, Edinburgh, , United Kingdom
Presentation Type: Paper
Location: Cottonwood C (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 11:45 AM