Format: ORAL

Michele Rodda1 Sigrid Liede-Schumann2

1 Singapore Botanic Gardens, National Parks Board, 1 Cluny Road, Singapore 259569, Singapore 2 University of Bayreuth, Department of Plant Systematics, Universitätsstr. 30, Bayreuth, 95440, Germany

A densely sampled molecular phylogeny of the pantropical, predominantly forest-dwelling tribe Marsdenieae, including almost a quarter of the ca. 740 species shows that the tribe is divided in two large clades, with two genera Rhyssolobium (southern Africa) and Sicyocarpus (Madagascar) placed outside of both clades. The first of the two large clades has a native distribution exclusively in Asia and the Pacific area. The type genus of the tribe, Marsdenia R.Br., is sister to all remaining genera of this clade, and comprises ca. 10 species. This clade harbours two species-rich radiations, Leichhardtia(ca. 80 species) in the Pacific realm and the Hoya-alliance (300 species). The second large clade shows a cosmopolitan distribution with several small Asian lineages as sisters to some larger genera of African-Asian distribution, as well as the New World genus Ruehssia (ca. 130 species). As far as known, all larger clades comprise species adapted to various types of pollinators (small and larger flies, bees, butterflies, moths), forcing highly similar floral structures. For the Hoya-alliance, we present a densely sampled phylogeny obtained using target enrichment and including ca. 80 % of the known diversity of Hoya and Dischidia, all taxa of Oreosparte (3 species) and Papuahoya (3 species). Dischidia, Oreosparte and Papuahoya are confirmed as monophyletic, but Hoya is paraphyletic, with a smaller clade sister to Papuahoya and a larger clade (Hoya s.s.) sister to Dischidia + Oreosparte. Within Hoya s.s., some clades are characterised by uniform flower morphologies while others, including the main radiation of species in New Guinea, independently developed a large range of flower morphologies. The largest molecular and morphological diversity of Hoya s.s. is found in Borneo. Our results will contribute towards a modern, stable classification of the Hoya-alliance, and studies on its origin and and diversification.