XVI International Botanical Congess

Wood structure and ITS sequences support the monophyly of several basally branching clades in Araliales, and offer insights into evolutionary patterns and potentially ancestral characters within the order. Astrotricha (Australia) and Osmoxylon (Malesia, Melanesia) are peripheral branches within core Araliaceae, and show several atypical features. Myodocarpus (endemic to New Caledonia) and Delarbrea (NC, 1 sp. in Queensland) comprise a second clade sister to core Araliaceae. Apiopetalum (endemic to NC) and Mackinlaya (Australia, Malesia) are closely related and sister to core Araliaceae or some Apiaceae: Hydrocotyloideae. The latter two groups, concentrated in New Caledonia/Australasia, are rather isolated within Araliales, as suggested by wood features. Pittosporaceae and four enigmatic southern hemisphere genera (Aralidium, Griselinia, Toricellia, Melanophylla) are closely related to Araliales, and suggest hypothesized ancestral features including simple leaves, a bicarpellate gynoecium, andromonoecy, a paniculate-umbellate inflorescence, ad paratracheal axial parenchyma and septate fibres in wood. Compound leaves appear to be derived, as does the dry, schizocarpic fruit of Myodocarpus.