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* Premise of the study: Solanum section Herpystichum is a lineage that comprises both widespread and very narrowly distributed species. This study investigates the phylogenetic relationships of sect. Herpystichum and evaluates several phylogenetic methods for analysis of multiple sequences. * Methods: Sequence data from seven nuclear (ITS, GBSSI, and five COSII) and three plastid (psbA-- trnH, trnT -- trnF, and trnS -- trnG) regions were concatenated and analyzed under maximum parsimony and Bayesian criteria. In addition, we used two analytical methods that take into account differences in topologies resulting from the analyses of the individual markers: Bayesian Estimation of Species Trees (BEST) and supertree analysis. * Key results: The monophyletic Solanum sect. Herpystichum was resolved with moderate support in the concatenated maximum parsimony and Bayesian analyses and the supertree analysis, and relationships within the section were well-resolved and strongly supported. The BEST topology, however, was poorly resolved. Also, because of how BEST deals with missing sequences, > 25% of our accessions, including two species, had to be excluded from the analyses. Our results indicate a progenitordescendent relationship with two species nested within the widespread S. evolvulifolium. * Conclusions: Analytical methods that consider individual topologies are important for studies based on multiple molecular markers. On the basis of analyses in this study, BEST had the serious shortcoming that taxa with missing sequences must be removed from the analysis or they can produce spurious topologies. Supertree analysis provided a good alternative for our data by allowing the inclusion of all 10 species of sect. Herpystichum. [ABSTRACT FROM AUTHOR]

Rainforests in tropical Australia occupy a very small, discontinuous area (<1% of the continent), yet they are floristically diverse (c. 2800 vascular species) with high endemicity. There is a distinctive Gondwanan and autochthonous element, and some of the world's ancestral links to the basal angiosperms are uniquely found here. Tile rainforests can be evergreen or deciduous, but there is a distinct dry season with intermittent drought years. With these characters, the evolutionary pressures on species may be very different to that experienced elsewhere. Sexual systems of 1113 tree species (83 families) from northern Australia were compared with published accounts from the paleo- and neotropics. Hermaphroditic systems dominated all tree floras, and within all floras but Australia dioecy was the most common unisexual system. In tropical Australia, however, significantly more monoecy than dioecy occurred at landscape and community levels. Incorporating phylogeny revealed that sex and fruit types are significantly clustered. The Euphorbiaceae and Sapindaceae contributed c. 50% of the monoecious taxa. Inefficient pollinators (e.g., beetles) may have favored the maintenance of monoecy at the expense of dioecy in the Australian tropics although <1% of the flora has been studied for pollinators and none of the monoecious tree species. [ABSTRACT FROM AUTHOR]