1. Department of Biology and Herbarium, Coker Hall CB 3280, University of North Carolina, Chapel Hill, North Carolina 27599-3280, USA
2. Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
3. Division of Mathematics, Science, and Engineering, Hartnell College, 411 Central Ave., Salinas, California 93901, USA