There were problems in the reproduction of some figures in both the original version of this article (Annals of Botany 100: 1491–1505, 2007) and a subsequent version reprinted in Annals of Botany 101: 483, 2008. The entire article is reproduced here with the original page numbers and can be accessed free of charge at www.aob.oxfordjournals.org. The publishers would like to apologize for these p...

Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic, e-mail: [email protected], [email protected], [email protected]; Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, CZ128 01 Prague, Czech Republic, e-mail: [email protected]; Department of Ecology, Faculty of Science, Charles University in Prague, Viničná ...