CIRCUMSCRIPTION OF MARSDENIA (ASCLEPIADACEAE, MARSDENIEAE), WITH A REVISION OF THE GENUS IN AUSTRALIA AND PAPUASIA

The genus Marsdenia R.Br. is circumscribed utilising data from taxonom ic history and morphology, and its relationship to other genera in the Marsdenieae is discussed. Genera that have usually been or commonly r egarded as distinct, i.e. Gymnema R.Br., Leichardtia R.Br., Bidaria (E ndl.) Decne, and Thozetia F. Muell. ex Benth., are discussed and consi dered congeneric with Marsdenia. A revision of the Australian and Papu asian (Irian Jaya, Papua New Guinea, Solomon Islands) taxa of Marsdeni a is presented and 78 species (one with two subspecies) and one putati ve interspecific hybrid are recognised. Forty-six taxa are accepted as new, namely Marsdenia ambuntiensis, M. archboldiana, M. argillicola, M. arfakensis, M. belensis, bilobata, bliriensis, M. brassii, M. brevi s, M. brunnea, M. carrii, M. connivens, M. cremea, M. destituta, M. di schidioides, M. divisicola, M. egregia, M. flavida, M. globosa, M. gra ndis, M. graniticola, M. hamata, M. kebarensis, M. lacicola, M. longip edicellata, M. millariae, M. mira, M. paludicola, M. papillosa, M. par va, M. poioensis, M. primulina, M. pumila, M. quadrata, M. rara, M. sp athulata, M. straminea, M. subglobosa, M. torsiva, M. trilobata, M. tu mida, M. urniflora, M. variabilis, M. venusta, M. viridiflora subsp. t ropica and M. volcanica. A new name, M. angustata, is provided to repl ace Bidaria erecta F.Muell. New combinations made are M. brevifolia (G ymnema brevifolium Benth.), M. geminata (Gymnema geminata R.Br.), M. m icradenia (Gymnema micradenium Benth.), M. muelleri (Gymnema muelleri Benth.), M. pleiadenia (Gymnema pleiadenia F.Muell.), M. rivularis (Gy mnema rivulare Schltr.), M. suborbicularis (Gymnema suborbiculare K.Sc hum.), M. tricholepis (Gymnema tricholepis Schltr.) and M. trinervis ( Gymnema triverve R.Br.). Lectotypes are chosen for a number of names. A putative hybrid is recorded between M, viridiflora subsp. viridiflor a and M, microlepis. Separate keys to the Australian and Papuasian spe cies of Marsdenia are given. Separate keys to the Australian and Papua sian genera of Asclepiadaceae are given.