1. Department of Biodiversity and Conservation, Real Jardín Botánico, CSIC, Plaza de Murillo 2, 28014 Madrid, Spain; 2INRA, UMR 1062 CBGP Campus International de Baillarguet, 34988 Montferrier-sur-Lez, France; 3Department of Biogeography and Global Change, Museo Nacional Ciencias Naturales-CSIC, 28006 Madrid, Spain; 4Department of Botany, Field Museum of Natural History, Chicago, IL 60605, USA and 5Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK