Polish Botanical Journal 47(1): xx-xx, 2002 THE ASSOCIATION GERANIO PHAEI-URTICETUM DIOICAE IN SOUTHWEST POLAND KRZYSZTOF S´ WIERKOSZ, ZYGMUNT DAJDOK & EWA SZCZE˛S´NIAK Abstract: Geranio phaei-Urticetum dioicae, a poorly known association of nitrophilous saum communities occurring in the moun- tains of Central Europe was characterized based on 39 phytosociological relevés. Its ecological requirements and distribution in Poland and Central Europe are presented and discussed. Five new subassociations of the Geranio phaei-Urticetum dioicae (G.-U. arrhenatheretosum elatioris, G.-U. typicum, G.-U. festucetosum giganteae, G.-U. senecionetosum fuchsii and G.-U. rumicetosum alpestris) have been distinguished on the basis of differing species composition. Key words: Nitrophilous saum communities, new syntaxa, Geranium phaeum, Convolvuletalia sepium, Artemisietea vulgaris, Poland Krzysztof S´wierkosz, Museum of Natural History, Wrocław University, H. Sienkiewicza 21, PL-50-335 Wrocław, Poland; e-mail:
[email protected] Zygmunt Dajdok & Ewa Szcze˛s´niak, Institute of Botany, Wrocław University, Kanonia 6/8, PL-50-328 Wrocław, Poland; e-mail:
[email protected];
[email protected] INTRODUCTION Most nitrophilous saum communities in Poland areas of low anthropopressure, occurring along have been the subject of numerous and detailed streams, river banks and forest roads, or in clear- studies. Work on determining their variability in- ings. One of these associations is Geranio phaei- tensified after Brzeg (1989) discussed the syntax- Urticetum dioicae Hadacˇ et al. 1969, whose dis- onomic division of the order Galio-Calystegieta- tribution, basic habitat conditions and lia sepium (R. Tx. 1950) Oberd. in Oberd. et al. differentiation is presented in this paper.