Systematic Foliar Morphology of Phyllanthoideae (Euphorbiaceae). III. Cladistic Analysis

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Abstract
Cladistic analysis of 43 foliar characters was used to explore the phylogeny of genera in Phyllanthoideae and to test the systematic value of foliar morphology. Character polarities were assessed by outgroup analysis treating other subfamilies of Euphorbiaceae and primitive genera in Flacourtiaceae as outgroups. Results indicated that several major tribes recognized in the most recent classification of the subfamily are essentially monophyletic, including Aporuseae, Bridelieae, Drypeteae, and most of Wieldandieae, whereas others, notably Antidesmeae, are probably paraphyletic. Conflicts between leaf-based cladograms and the previous classification appeared in the relationships of Astrocasia, Didymocistus, Neowawraea, and genera in Amanoeae, but relationships were clarified for genera like Bischofia, Uapaca, and Hymenocardia, whose positions have previously been obscure. These results verify the systematic value of foliar characters. However, the rates of homoplasy found in this study are higher than found in most cladistic analyses, possibly indicating that many foliar characters are of most value at lower taxonomic levels. Relatively conservative characters include outer vein loop size, tertiary vein pattern, aerolation development, unicellular trichome type, and tanniniferous epidermal cells.