Read the next issue of Agriculture, Ecosystems and Environment Journal and note paper by CLements at al. Dr. C.J.Swanton, Associate Professor, Weed Ecology, Department of Crop Science, Univ. of Guelph, Guelph, Ontario. N1G 2W1 Email: cswanton@crop.uoguelph.ca Fax: 1-519-763-8933 Phone: 1-519-824-4120 Ext. 2512