1. Department of Botany and Plant Pathology; Oregon State University; Corvallis OR 97331-2902 USA
2. Smithsonian Tropical Research Institute; Balboa, Ancón Republic of Panama
3. CSIRO Ecosystem Sciences; Atherton Qld 4883 Australia
4. Department of Ecology and Evolutionary Biology and Herbarium; University of Michigan; Ann Arbor MI 48109-1048 USA