1. 1Programa de Pós-Graduação em Botânica, Departamento de Biologia, Universidade Federal Rural de Pernambuco, 52171-900, Recife, PE, Brazil
2. 2Herbarium, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, UK
3. 3School of Biological Sciences, University of Portsmouth, Portsmouth, PO1 2DY, UK; Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska 99775, USA