1. Botany Unit; Finnish Museum of Natural History; University of Helsinki; P.O. Box 44 00014 Helsinki Finland
2. Department of Biological Sciences; 100 Galvin Life Sciences Center; University of Notre Dame; Notre Dame Indiana 46556 USA
3. U.S. Geological Survey; Great Lakes Science Center; 1574 N 300 E Chesterton Indiana 46304 USA
4. Energy and Resources Group; 310 Barrows Hall, University of California at Berkeley; Berkeley California, 94720 USA
5. Institute of the Environment; 1954 Buford Ave, St. Paul; MN 55108 University of Minnesota USA