1 Laboratoire Écologie, Systématique, Évolution, Université Paris-Sud, CNRS UMR 8079 91405 Orsay, France herve.sauquet@u-psud.fr swgraham@interchange.ubc.ca.
2 UBC Botanical Garden & Centre for Plant Research, and Department of Botany, 6270 University Boulevard, University of British Columbia, Vancouver, British Columbia V6T 1Z4 Canada herve.sauquet@u-psud.fr swgraham@interchange.ubc.ca.