1. Department of Botany, Masaryk University, Kotlářská 2, CZ‐611 37 Brno, Czech Republic; Fax +420541211214; E‐mail
2. Merhautova 151, CZ‐613 00 Brno, Czech Republic
3. Institute of Ecology and Botany, Hungarian Academy of Sciences, H‐2163 Vácrátót, Hungary; E‐mail