The wax flowers and their complex relationship

 Wax flowers and many related plant genera arose about 33 million years ago. Shortly thereafter, a new international study led by Bayreuth's botanist, Dr. Dr., split them into his three independent evolutionary lineages. Sigrid Riede-Schumann show. A total of 740 species in 37 genera occur and are distributed in tropical and subtropical regions around the world. Only a combination of well-founded morphological studies and modern molecular genetic analysis methods can ensure accurate taxonomic description and classification. The research results were published in the specialized journal "Taxon".

Originating in the Oligocene, waxflowers form the plant genus Hoya, named after the English gardener Thomas Hoy. It belongs to a large plant family of the Dogbane family (Apocynaceae). Researchers from Bayreuth, Singapore, Le Mont d'Or (France, New Caledonia), Brisbane (Australia) and Philadelphia (USA) have reexamined the evolution of wax flowers and their complex relationships. Results: Marsdeniae can be assigned to three different developmental lineages of her that formed over 30 million years ago. The small lineage includes only a few surviving species, the so-called Relict species, that live only in South Africa and Madagascar. However, his two other lineages are much more abundant, with about 360 species each, and have quite different biogeographic histories. One of these is confined to Southeast Asia and the Pacific Islands. Many different species are now widespread in Australia, New Caledonia and New Guinea. The New Caledonian breed from Australia he arrived in two waves. This lineage includes waxflowers, which are popular ornamental plants, but also broadleaf indigo (Marsdenia tinctoria), for example. The other lineage spread throughout the tropics and subtropics of the Old World, reaching tropical America about 21.5 million years ago. From here, about 130 species spread into what is now the tropics, including Cundurango (Ruehssia cundurango), a climbing shrub known for its medicinal properties.

The discovery of these three evolutionary lineages was only possible because targeted molecular genetic studies of Marsdenieae were performed for the first time in addition to long-established morphological studies in plant phylogeny.

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