BLUMEA 48: 319 – 391 Published on 11 July 2003 doi: 10.3767/000651903X675017 REVISION OF THE MALESIAN AND THAI SPECIES OF SAUROPUS (EUPHORBIACEAE: PHYLLANTHOIDEAE) PETER C. VAN WELZEN Nationaal Herbarium Nederland, Universiteit Leiden branch, P.O. Box 9514, 2300 RA Leiden, The Netherlands; e-mail:
[email protected] SUMMARY Fourteen species of Sauropus are recognised for Malesia, 21 for Thailand. Two species are described as new, S. asymmetricus of Sumatra and S. shawii of Borneo. Many new synonyms, especially for S. androgynus and S. rhamnoides, are provided. The latter two species have a much wider distribu- tion than described before and both are difficult to separate from each other. A phylogeny based on morphological and palynological data proved futile, but showed that Sauropus together with Breynia and Glochidion are embedded in the paraphyletic Phyllanthus. Most species which formerly belonged to Synostemon and are now included in Sauropus are probably, with the exception of S. bacciformis, related to Breynia and Glochidion. Because of the poor phylogenetic results the circumscription of Sauropus is not changed (Synostemon still included), and an infrageneric classification is not provided. Key words: Euphorbiaceae, Sauropus, Synostemon, Malesia, Thailand. INTRODUCTION Blume (1825) introduced Sauropus based on two species, S. rhamnoides and S. albi cans. The latter, the lectotype of the genus (Webster, 1994), appeared to be a synonym of a taxon originally described by Linnaeus (1767) as a Clutia, the commonly known S. androgynus (L.) Merr. In the course of time various authors contributed taxa and presently about 70 species are known. The genus shows two distinct areas of speciation, one in Southeast Asia mainland (Thailand up to Vietnam) and one in Australia.