EN
The aim of this study is to show the role of Lolium perenne L. in the carpet plant communities which develop on trampled places such as: roadsides, wastelands, playgrounds, sport fields, lawns, railway areas in the Upper Silesian Industrial District. In order to recognise plant communities there were made 120 phytosociological relevés. There were recognized 5 plant communities which are built mainly by annuals from Polygono-Poëtea class (Polygonetum calcati, Sagino-Bryetum, Puccinellio-Chenopodietum, Poëtum annuae, Matricario-Polygonetum) and 5 in structure of which the main role play hemicryptophytes from Molinio-Arrhenatheretea class, Trifolio-Plantaginetalia order, Cynosurion (Lolio-Plantaginetum, Juncetum macri), and Agropyro-Rumicion (Potentilletum anserinae, Potentilletum reptantis, Odontites serotine community) alliances. In carpet plant communities occur from 3 to 25 grasses, and their participation in the floristic list range from 12% to 32%. Lolium perenne was recorded in almost each plant community with the exception of Sagino-Bryetum. The highest percentage participation in the plant cover it has in Odontites serotina community and Lolio-Plantaginetum phytocoenoses. In the lalter one it has it ecological optimum.