Revisionary Studies in 'Cucurbitaceae' Tribe 'Benincaseae' with Special Reference to Australia

Abstract

Radical changes to concepts of relationships in Cucurbitaceae previously based on morphology have been made through phylogenetic analyses using multigene datasets. The Australian representation of 'Cucurbitaceae' tribe 'Benincaseae' is now considered to consist of eight indigenous genera including 'Muellerargia' Cogn., 'Zehneria' Endl. and 'Cucumis' L. from the subsumed tribe 'Melothrieae'. A phenetic analysis of 'Zehneria' using PATN has shown the genus in Australia to consist of at least two species, 'Z. cunninghamii' F.Muell. and an unnamed species previously referred to 'Z. mucronata' (Blume) Miq. Results were equivocal on the conspecificity of 'Z . baueriana' Endl. and 'Z. mucronata'. Phylogenetic analysis using PAUP was conducted on a molecular dataset from nuclear and plastid sequences of 75 taxa. Results indicated a new genus 'Austrobryonia' H.Schaef. must be segregated from 'Cucumis' ('Mukia') and is the closest living relative of the Eurasian and Mediterranean 'Bryonia' L. and 'Ecballium' L. of tribe 'Bryonieae'. 'Austrobryonia micrantha' (F.Muell.) I.Telford, 'A. argillicola' I.Telford, 'A. pilbarensis' I.Telford and 'A. centralis' I.Telford are endemic to inland Australia.