About weed plants of waste grounds of St. Petersburg

The purpose of the study is to identify the features of the species composition of weeds in the waste grounds located in the Krasnoselsky district of St. Petersburg. Waste grounds monitoring for weeds, floristic analysis of the obtained data, calculation and assessment of species occurrence were carried out. The analysis revealed 95 species of weed plants from 70 genera and 20 families. Most species and genera belong to 6 families. Perennial species predominate in life expectancy (62.11 %). According to the occurrence indicators, species are distributed according to the classes of constancy (I class - 49 species, II - 18, III - 9, IV - 8, V - 11). A group of 28 dominating species by occurrence was identified (V, IV, III classes of constancy). Identified A group of 18 associated species by occurrence was identified (II constancy classes). The presence of 24 species of weeds dominating the fields of grain and row crops in the Leningrad Region, on the surveyed waste grounds was revealed. A number of alien species have been identified, some of which are burdensome weeds in the southern regions of Russia, and others are dangerous invasive species.