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ItemPhylogeny and biogeography of section Botrycephalae (Acacia subgenus Phyllodineae)(University of Melbourne, 2000)Section Botrycephalae (Acacia subgenus Phyllodineae) comprises approximately 40 specific and infraspecific taxa. The section is restricted to South Eastern Australia, extending from South Eastern Queensland to Tasmania and the south eastern part of South Australia. The section is characterized by adult plants retaining bipinnate leaves, stipules not spinescent and capitulate inflorescences arranged in racemes. The sister group to the Botrycephalae is section Phyllodineae, including Acacia podalyriifolia and A. ligulata, which form a monophyletic group (Chappill and Maslin, 1995). These species and A. calamifolia (Phyllodineae) were used as outgroups for a phylogenetic analysis of the Botrycephalae. The cladistic analysis was based on a data set of morphological, anatomical and seedling characters, using parsimony methods. Both qualitative and quantitative characters were coded. Most of the multistate characters were treated as ordered characters to allow linear transformation with states of equal value. Some characters were not variable across the section and other characters showed a high level of homoplasy. Due to the predominance of quantitative data, a phenetic analysis was also conducted for the ingroup taxa using the same data set as in the cladistic analysis. Although relationships within section Botrycephalae were not fully resolved, some subclades were defined with confidence (well-supported by jackknife values). A provisional infrasection classification of the Botrycephalae is proposed. Based on the phylogenetic analysis three series and six subseries are recognised. Those three series are Latisepalinae, Fulvinae and Mearnsinae. Series Latisepalinae, including subseries Elatae, Pruinosae and Decurrenae, is not monophyletic and includes taxa that formed unresolved basal nodes in the cladograms; it requires further analysis using molecular data. Series Fulvinae comprises three species: A. silvestris, A. fulva and A. mollifolia. Approximately half of the members of the section are included in the series Mearnsinae which, is further divided into three subseries: Jonesiae, Mearnsiae and Deaneae. The taxon cladogram was also used to analyse historical area relationships within eastern Australia. The method of sub-tree analysis (using the program TASS, Nelson and Ladiges, 1995) was employed. The biogeographic pattern suggested that some speciation relates to vicariance events but that the present distribution of some species is also due to dispersal.