Seed reproduction of running wild plant species in conditions of Southern Karelia

One of the indicators of introducents’ vitality is seed production. We studied indicators of seed reproduction in herbaceous species, which are becoming wild in the north, and their invasive possibility. The model objects were Echinocystis lobata (Michaux) Torr. & A. Gray, Lupinus polyphyllus Lindl., Xanthoxalis stricta (L.) Small, Symphytum asperum Lepech., Calendula officinalis L., Centaurea montana L., Helianthus tuberosus L. These species are often cultivated as adornment plants in the region. We found out that Xanthoxalis stricta had the highest rate of seed production (average 1096,2 seeds, germination is 14,8 %). For other species those indices were: Helianthus tuberosus - 249,0 (germination 17,9 %); Lupinus polyphyllus - 184,8 (70,2 %); Calendula officinalis - 172,8 (36,4 %); Echinocystis lobata - 164,7 (40,1 %); Symphytum asperum - 107,4 (25,3 %); Centaurea montana - 14,4 (40,3 %). The indices of seed reproduction of Xanthoxalis stricta and Lupinus polyphyllus are close to that of Impatiens glandulifera Royle. (invasive species for Karelia). Xanthoxalis stricta spreads primarily on cultural sites, Lupinus polyphyllus settles on disturbed and secondary habitats. The model species have steady seed reproduction in northern conditions. But this capacity is not sufficient for wide dissemination from places of cultivation and, therefore, for transition into the category of invasive species. Lupinus polyphyllus can be considered potentially invasive species.