Formalized classification of the weed vegetation of arable land in Slovenia

A phytosociological synthesis of weed vegetation in Slovenia using the Braun-Blanquet approach was performed. Historical and new data (482 relevés after stratified resampling) were used and classified formally using the Cocktail method. Eleven different syntaxa: Kickxietum spuriae, Galio tricornuti-Ranunculetum arvensis, Geranio-Allietum, Mercurialietum annuae, Veronicetum trilobae-triphyllidi, Alchemillo-Matricarietum, basal community Alchemilla arvensis-[Scleranthion annui], Panico-Chenopodietum, Hyoscyamo-Chenopodietum hybridi, Galeopsido-Galinsogetum, Echinochloo-Setarietum were distinguished and are presented in a synoptic table. Ecology, diagnostic and constant species, distribution and threats to weed syntaxa are presented. Delimitation of the high-mountain association Galeopsido-Galinsogetum presents problems as it is species-poor and is composed of generalist species. Some problems of using the Cocktail method to classify species poor stands are pointed out. Comparison of classified syntaxa and their diagnostic species in Slovenian and Moravian datasets shows that there are in both areas common central asociations of higher syntaxa, which are widely distributed in Central Europe: Veronicetum trilobae-triphyllidi, Alchemillo-Matricarietum, Panico-Chenopodietum and Echinochloo-Setarietum. There are differences in various classifications of vernal communities and those that thrive in only one area.