1. Dept of Botany; Univ. of Hawai'i at Mānoa; Honolulu HI 96822 USA
2. MTT Agrifood Research Finland; FI-31600 Jokioinen Finland
3. Section of Ecology, Dept of Biology; Univ. of Turku; FI-20014 Turku Finland
4. Dept of Biology; Washington Univ. in St. Louis; 1 Brookings Drive, Box 1137 St. Louis MO 63130 USA
5. School of Biological Sciences, Royal Holloway Univ. of London; Egham, Surrey TW20 0EX UK