1. Department of Systematic and Evolutionary Botany; University of Zürich; Zürich Switzerland
2. Institut de Systématique, Évolution, Biodiversité (ISYEB); UMR 7205 CNRS MNHN UPMC EPHE; Muséum national d'Histoire naturelle; Sorbonne Universités; Paris France
3. Department of Plant Taxonomy and Nature Conservation; University of Gdansk; Gdańsk Poland
4. Institute of Organic Chemistry; University of Hamburg; Hamburg Germany
5. Agroecology and Pollination Group; Landscape Ecology and Plant Production Systems; Université libre de Bruxelles (ULB); Brussels Belgium
6. Department of Biology; University of Naples Federico II; Naples Italy