[1] Kew, Royal Bot Gardens, Surrey TW9 3AB, England
[2] Univ Nottingham, Sch Geog, Nottingham NG7 2RD, England
[3] Nat Hist Museum, Dept Life Sci, Cromwell Rd, London SW7 5BD, England
[4] Univ Alaska, Univ Alaska Museum, 907 Yukon Dr, Fairbanks, AK 99775 USA
[5] Royal Bot Gardens, Edinburgh EH3 5LR, Midlothian, Scotland
[6] Oregon State Univ, Dept Bot & Plant Pathol, 2082 Cordley Hall, Corvallis, OR 97331 USA
[7] New York Bot Garden, Bronx, NY 10458 USA
[8] Ctr Australian Natl Biodivers Res, CSIRO Australian Natl Herbarium, GPO Box 1700, Canberra, ACT 2601, Australia
[9] Australian Natl Univ, Ctr Biodivers Anal, Acton, ACT 2601, Australia
[10] Utah State Univ, Dept Wildland Resources, 5230 Old Main Hill, Logan, UT 84322 USA
[11] Stockholm Univ, Royal Swedish Acad Sci, Bergius Fdn, SE-10691 Stockholm, Sweden
[12] Stockholm Univ, Dept Ecol Environm & Plant Sci, SE-10691 Stockholm, Sweden
[13] Boise State Univ, Dept Biol Sci, 1910 Univ Dr, Boise, ID 83725 USA