1. Department of Botany, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4 (T.L.W., J.B., W.L.T., D.J.S., G.W.H.); and
2. Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 (L.M.-M., B.A.M.)