Patricia L. Dysart, Depts. of Crop and Soil Science/Range Ecology and Management, Oregon State University, 107 Crop Science Building, Corvallis, OR 97331, William C. Krueger, Department of Range Ecology and Management, Oregon State University, 202 Strand Agricultural Hall, Corvallis, OR 97331, Carol A. Mallory-Smith, Dept. of Crop and Soil Science, Oregon State University, 107 Crop Science Building, Corvallis, OR 97331, and Jan F. Stevens, College of Pharmacy, Oregon State University, 203 Pharmacy Bldg., Corvallis, OR 97331.