Rupert Barneby and his legume legacy
Luckow, Melissa , Miller, Joseph T. , Jobson, Richard , Murphy, Daniel J. .
Generic relationships in the Mimosoideae (Fabaceae).
In order to construct a phylogeny of the subfamily Mimosoideae, we sequenced four chloroplast gene regions (matK, ndhF, trnL-F, trnK) across a wide range of 165 mimosoid taxa. A preliminary matrix of morphological characters was also coded for these taxa. Analysis of the combined matrix revealed that the sister group to the Mimosoideae is the caesalpinioid genus Erythrophleum rather than Dimorphandra, as had often been hypothesized. The engimatic Mimozyganthus, previously considered to be transitional between the Mimosoideae and Caesalpinioideae and assigned its own tribal status, is demonstrated to be nested within the Mimosoideae, and closely related to its Argentine relatives Piptadeniopsis and Prospidastrum. Xerocladia, a monotypic genus from South Africa, is shown to be sister to Prosopis. The large (ca. 1400 species) genus Acacia is polyphyletic and must be recircumscribed as at least five separate genera, to include Acacia s.s., Racosperma, Senegalia, Acaciella, and a new genus. Piptadenia is likewise polyphyletic and a more detailed analysis of this group has been undertaken. Some morphological characters previously considered to be highly homoplasious, such as armature, are surprisingly conserved. However, this phylogeny also bears out previous observations that fruit type is highly plastic in the mimosoids. The basal members of the Mimosoideae comprise mainly African species of wet habitats, and the adaptation to seasonally dry and arid habitats led to generic and specific diversity in this large group of legumes.
1 - Cornell University, L.H. Bailey Hortorium, Department of Plant Biology, Ithaca, New York, 14853, U.S.A.
2 - University of Melbourne, School of Botany, Parkville, Victoria, 3052, Australia
3 - University of Iowa, Biology Department, 138 Biology Building, Iowa City, Iowa, 52242, USA
Presentation Type: Symposium
Location: Magpie (Cliff Lodge)
Date: Monday, August 2nd, 2004
Time: 3:00 PM