Problem of rare species surviving in the territories with intensive human impact especially in megalopolis area and problem of invasions are very actual. Saint-Petersburg – one of the biggest cities in Europe – has highly dynamical flora that has lost and losing some forest, swamp and seashore species and has acquired and acquiring plant species. Centaurium erythraea and Tripolium vulgare inhabiting biotopes connected with seashore grew in the past on the territory of St. Petersburg but disappeared, they are include in Red Data Book of neighboring Leningrad region. Our inventory of flora and vegetation on the territory of Toyota Motor factory on the south suburb of St. Petersburg that is not near the seashore has shown that these 2 species grow in 2 patches on bulk soil with wild
lawn. Centaurium erythraea grows in low-herbs meadows with different grass cover, some but not all of these plant communities are mowed sometimes. Tripolium vulgare is met in wet meadows and swamp communities that are never mowed. There are plant communities with high abundance of C. erythraea or T. vulgare. These species were not planted on the lawn. Seems their seeds reached this place with bulk soil. May be it can turn out a model for forming artificial populations of rare species.