In the spontaneous flora of the V.N. Rzhavitin Botanical Garden, 31 wild inroducents from 27 genera and 13 families were identified, which is 7 % of the total number of cultivated tree species. The greatest tendency towards naturalization is shown by immigrants from North America and the Far East (12 and 8 species, respectively). Species of the Rosaceae family predominate (11 species). Some species have already become firmly part of the spontaneous flora (Acer negundo L., Physocarpus opulifolius (L.) Maxim., Parthenocissus inserta (A. Kern.) Fritsch, Lonicera tatarica L., Fraxinus pennsylvanica Marsh., Cornus alba L.), others – while maintaining current trends towards naturalization, will replenish its composition in the future.

For the territory of the city of Tobolsk (Tyumen region), the growth of 15 macrophytes is registered known as alien species for the region. The article provides information about their distribution within the city and its environs, the nature of occupied ecotopes, and adventitious status. One species (Elodea canadensis Michx.) is classified as transformer, two ones (Impatiens glandulifera Royle, Phragmites altissimus Mabille) are classified as invasive plants; one species (Iris pseudacorus L.) is classified as escaped from cultivation plant. The rest are classified as alien species that have naturalized in anthropogenic habitats. Three species (Acorus calamus L., Caulinia minor Coss. et Germ., Zannichellia repens Boenn.) are listed in the Red Book of the Tyumen region, but the nature of their growth in the area under consideration does not allow them to be classified as native plants. We have made a proposal to remove them from the regional Red Book and consider them as naturalized alien species (epyocophytes).

A total of 1124 species of Pteridophyta (including Lycopodiopsida) from 170 genera and 38 families have been identified in the Socialist Republic of Vietnam. Many species are quite widespread not only in natural habitats, but are also present in arable land and in urban plant communities. In ruderal and synanthropic habitats we noted 82 species from 38 genera and 17 families, among which 20 are introduced species, and 62 are native species that can occupy biotopes and cenoses that are not typical for them in nature. Most fernlike plants were observed in the synanthropic and disturbed habitats. The government of Vietnam is actively developing a legislative framework on the issues for combating alien species, yet those domestic standards need to be brought into line with international ones.

The purpose of the study is to identify the composition and analyze frequency and stability of alien plant species in phytocenoses of lawns in the central part of the Kursk city. 37 neophyte species have been identified, which is 27.4 % of the identified flora. The most common of these is Lolium perenne L. , a species that is used for sowing on lawns. Among other species, the most common are Geranium sibiricum L., Erigeron canadensis L., Sonchus oleraceus L. Monodominant communities on lawns are formed by neophytes Atriplex tatarica L., Cyclachaena xanthiifolia (Nutt.) Fresen., Geranium sibiricum, Parthenocissus inserta (A. Kern.) Fritsch.

Features of the stomatal apparatus can be used to assess the adaptive capabilities of alien species. Native Quercus robur L. and introduced Quercus rubra L. grow together in the arboretum of the Main Botanical Garden of the RAS and do not differ significantly in stomatal density (363.1±6.3 pcs./mm² in and Q. robur 369.8±4.7 pcs./mm² in Q. rubra), while the relative transpiration area index of Q. rubra is 1.3 times higher than that of Q. robur (20.9 % and 15.7 %, respectively). In addition, in Q. rubra it exceeds 12 %, and it can be assumed that in the future there will be an expansion of its secondary range with an increase in invasive activity.

As a result of long-term monitoring, it was established that the alien dendroflora of the Lower Amur region is represented by 27 species. All species are refugees from culture. For each species, the degree of naturalization is established on a nine-point scale. Four species are invasive (Acer negundo L., Hippophaё rhamnoides L., Parthenocissus inserta (A. Kerner) Fritsch., Prunus tomentosa Thunb.) and four species (Amelanchier spicata (Lam.) C. Koch, Rosa×rugosa Thunb., Populus alba L., Ulmus pumila L.) are potentially invasive. The remaining species, due to their biological characteristics, do not pose a threat of biological pollution. The emergence of new potentially invasive species is associated both with the cultivation of ornamental and fruit-bearing trees and shrubs by the population, and with urban landscaping.

Data on alien plant species of East Asian origin in the Ivanovo region are presented. By 2024, 43 species in total has been recorded in Ivanovo region, with the primary habitats located in East Asia. They belong to one division, 2 classes, 20 families and 36 genera. The most numerous are the Rosaceae family (10 species) and the Poaceae family (9 species). The peculiarity of EastAsian species is their high ability to naturalization: 19 species (44.2 %) of these have become invasive, 10 species (23.3 %) have penetrated into natural communities, competing with native species.

Seed propagation of Acer negundo L. was studied in the city of Petrozavodsk (Republic of Karelia). Fruit sizes correspond to the species characteristics. The weight of monospermous mericarps is 22.1–36.2 mg. Seed germination is 11–16 %. The number of flowers, fruits and seeds per 1 total meter of last year’s shoot growth was determined. The number of flowers on female trees is 274–501, on male trees – 295–540 per 1 meter. The number of fruits is 143–355, on average 274 fruits, 548 seeds per 1 meter. Seed set is 72 %. Self-seeding is limited. is an invasive species for many regions of Russia. In Karelia it does notAcer negundo manifest itself as an invasive species. The plant should not be excluded from urban greening.

A total of 78 species of alien neophytes from 71 genera and 61 families have been registered in the flora of «Pleshcheyevo Lake» National Park, that is 9.5 % of the total flora composition. The group of invasive species includes 34 species, 2 species are potentially invasive. The invasive activity of most species is low (index is 1–2) and is reduced to colonization of anthropogenically transformed, semi-natural and natural habitats. The analysis of the main directions of alien and invasive species spread in a specially protected natural area in Yaroslavl region, presented in this work, can be a background for providing monitoring research.

The widespread distribution of Ambrosia artemisiifolia in plant communities leads to various changes in the vegetation cover. In general, 32 geobotanical descriptions involving ragweed have been analyzed in the Rostov region. There are 6 associations (Ambrosietum artemisiifoliae, Melilotetum albo-officinalis, Odontito-Ambrosietum artemisiifoliae, Ambrosio artemisiifoliae-Melilotetum officinalis, Ambrosio artemisiifoliae-Cirsietum arvensis, Ambrosio artemisifoliae-Chenopodietum albi) which belong to 3 unions and 3 classes.