Systematics of the Austral-Pacific family Goodeniaceae: Establishing a taxonomic and evolutionary framework

The Goodeniaceae, close relatives of the Asteraceae, are a conspicuous part of the flora of Australia and many islands in the Pacific. A comprehensive molecular phylogenetic analysis of the family using cpDNA regions trnL-F and matK is presented, including representatives of all genera and nearly half the species. The family resolves into the two large clades: 'LAD' (Lechenaultia, Anthotium, Dampiera) and 'Core Goodeniaceae' (Brunonia, Scaevola, Diaspasis, Coopernookia, Goodenia, Selliera, Velleia, Verreauxia, Pentaptilon), which are also supported by morphological characters. The former Brunoniaceae, comprising the single species Brunonia australis, is clearly placed within the Goodeniaceae as sister to the remainder of Core Goodeniaceae while possessing many autapomorphic characteristics. Current subgeneric taxonomic groups are partially supported as monophyletic within Goodenia and Dampiera, but are generally non-monophyletic within Lechenaultia and Scaevola. Fruit types and floral traits involved in pollination and adaptations to aridity have evolved in a highly convergent fashion within several major clades. Rates of molecular evolution and number of extant taxa differ at several points between sister clades, particularly between Brunonia and the rest of Core Goodeniaceae, and between Scaevoia s.l. and Goodenia s.l. Future taxonomic changes will involve the synonymization of Selliera and monotypic Diasposis and, pending more comprehensive taxon and molecular sampling, the large, paraphyletic genus Goodenia may be split into at least three genera.