Revisionary Studies in 'Synostemon' (Phyllanthaceae, Phyllantheae): Morphological and molecular data corroborate generic recognition of 'Synostemon' and with increased species diversity

Abstract

Phylogenetic analysis using an expanded data set of nrDNA ITS and PHYC and cpDNA accD and trns sequence data retrieves a monophyletic 'Synostemon' F.Muell. ('Phyllanthaceae, Phyllantheae, Flueggineae'), previously subsumed into 'Sauropus' Blume or 'Phyllanthus L. Sauropus s. str.', excluding 'Synostemon', is shown to be nested within 'Breynia' J.R.Forst. & G.Forst. (Chapter 2). Morphological data clarifies infrageneric relationships within 'Sauropus' and its species are transferred to 'Breynia' in a new subgenus, 'B. subgenus Sauropus' (Blume) Welzen & Pruesapan (Chapter 3). 'Synostemon hamersleyensis' I.Telford & Naaykens, a recently discovered new species endemic to ironstone detrital formations of the Hamersley Range in the Pilbara, central Western Australia, is named, its distribution, habitat and contentious conservation status discussed (Chapter 4).