XVI International Botanical Congess

Morphological analyses were conducted using 41 characters for 36 genera, including some Onagraceae, Trapaceae and Combretaceae (outgroup). Results support Onagraceae as sister family to a monophyletic Lythraceae s.l. and Trapaceae as sister to ONAG and LYTH. A lythracean monophyly is synapomorphic for grouped vessels and a multi-celled archesporium. Innovations leading to the Lythroideae are a superior ovary and seed compression. Further divergence in Lythroideae to 2 clades of 14 genera each is weakly supported by homoplastic floral features. Each clade comprises equal numbers of Old and New World genera. Separate and combined morphological and rbcL data for a subset of 24 taxa consistently supported 3 clades of 8 genera. The inclusion of Trapa in the Lythraceae is supported by the molecular and combined analyses.