1. Duke University, Department. of Biology, Box 90338, Durham, NC 27708 USA;
2. Department of Botany, National Museum of Natural History, Smithsonian, Institution, PO Box 37012, Washington, DC 20013‐7012 USA and Smithsonian Institution, Museum Conservation Institute, 4210 Silver Hill Road, Suitland, MD 20746 USA;
3. Present address: Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh EH3 5LR, UK.