1. Department of Ecology and Evolutionary Biology University of Tennessee Knoxville 569 Dabney Hall Knoxville TN 37996 U.S.A.
2. Department of Geography, Environmental Management and Energy Studies University of Johannesburg APK Campus, Auckland Park Johannesburg 2006 South Africa
3. Faculty of Agronomy University of Parakou Parakou BP 123 Benin
4. Department of Botany University of Hawai'i at Mānoa 3190 Maile Way, 101 Honolulu HI 96822 U.S.A.