1. Graduate School of Environment and Information Sciences; Yokohama National University; 79-7 Tokiwadai, Hodogaya-ku Yokohama 240-8501 Japan
2. Center for Environmental Biology and Ecosystem Studies; National Institute for Environmental Studies; 16-2 Onogawa Tsukuba Ibaraki 305-8506 Japan
3. College of Education; Yokohama National University; 79-2 Tokiwadai, Hodogaya-ku Yokohama 240-8501 Japan
4. Department of Botany; University of Hawai'i at Manoa; 3190 Maile Way, Room 101 Honolulu HI 96822 USA