1. Department of Biology; University of Washington; Box 355325, Seattle Washington 98195-5325 U.S.A.
2. Department of Plant Biology; University of Georgia; 4504 Miller Plant Sciences Building Athens, Georgia 30602 U.S.A.
3. University of Washington Botanic Gardens; College of Forest Resources; Box 354115, Seattle Washington 98195-4115 U.S.A.
4. Royal Botanic Gardens; College of Forest Resources; Kew, Richmond Surrey TW9 3AB U.K.
5. School of Plant Science; University of Tasmania; Private Bag 55, Hobart Tasmania 7001 Australia