1. Department of Biosciences University of Oslo PO Box 1066, Blindern 0316 Oslo Norway
2. Department of Plant and Soil Science Texas Tech University PO Box 42122 Lubbock TX 79409 USA
3. School of Biological Sciences University of Aberdeen Aberdeen AB24 2TZ UK
4. The James Hutton Institute Craigiebuckler Aberdeen AB15 8QH UK
5. Department of Forest Mycology and Plant Pathology Uppsala BioCenter Swedish University of Agricultural Sciences PO Box 7026 SE‐75007 Uppsala Sweden