In this study, 56 adventive species have been identified in Khakas flora to date. In terms of the introduction method, xenophytes dominate; this group is composed of 44 species, which is 78.6% of all the adventive species under study. The ergasiophyte group consists of 12 species (21.4%). According to the naturalization degree, we identified three groups: epecophytes, agriophytes, and ephemerophytes. The epecophyte group is in the lead and consists of 21 species (37.5%). The agriophytes are represented by 19 invasive species (33.9%). The ephemerophyte group is composed of 16 species (28.6%). Thus, the ratios of the synanthropic-plant groups defined according to the introduction method and naturalization degree indicate that most of these adventive plants have been introduced unintentionally and successfully established themselves on a territory new to them. The adventive fraction of natural ecosystems in Khakas flora contains 20 species included in the report “The Black Book of the Flora of Siberia” [1].

In the course of field research, analysis of previously published works and viewing materials stored in the herbarium of the Central Siberian Botanical Garden SB RAS named after I. M. Krasnoborov (NS) we clarified an information on the distribution of rare adventive plant species in the territory of the Upper Yenisei basin. Cosmos bipinnatus, Ipomoea hederacea, Setaria maximowiczii and Sonchus oleraceus were noted for the first time in the Tuva flora. Grossularia reclinata in the Western Sayan, and Polygonum calcatum and Spergula vulgaris in the territory of Khakassia. Echinochloa crusgalli, Fagopyrum esculentum, Fragaria ananassa, Galium mollugo and Grossularia reclinata were new to the flora of the Sayano-Shushensky nature reserve. For 14 rare species new localities were noted and the boundaries of the ranges were specified: Amaranthus albus, Carduus nutans, Echinochloa crusgalli, Epilobium adenocaulon, Galium aparine, G. mollugo, Hordeum jubatum, Lactuca serriola, Oenothera hiennis, Portulaca oleracea, Psammophilliella muralls, Setaria faberi Sisymbrium loeselii, Spergula vulgaris.

As a result of the field work, analysis of earlier published works and viewing herbarium material in Institute of Botany, RAS (LE), Central Siberian Botanical Garden, SB RAS (NS, NSK), Altai State University (ALTB), Tomsk State University (TK), Krasnoyarsk State Pedagogical University (KRAS), State Natural Biosphere Nature Reserve "Sayano-Shushensky" (SSHZ), and State Nature Reserve "Azas", a data on rare native and adventive plant species in southern Central Siberiawere have been clarified. For the first time 2 species: Amblynotus rupestris, Ranunculus chinensis were discovered in Krasnoyarsk Territory; 3 species: Galinsoga parviflora, Physocarpus opulifolius, Ranunculus chinensis in Khakasia and 3 species: Oxytropis suprajeniseensis, Polygonum borgoicum, Polygonum tenuissimum in Tyva. New locations were noted, and range borders were refined for 19 rare species: Actaea erythrocarpa, Amblynotus rupestris, Calla palustris, Cypripedium x ventricosum, Cystopteris sudetica, Dendranthema sinuatum, Draba cinerea, Eranthis sibirica, Eritrichium tuvinense and others. Four species: Amblynotus rupestris, Ranunculus chinensis, Sparganium gramineum, Vicia hirsuta-turned out to be new to the flora of "Sayano-Shushensky" Nature Reserve; Actaea erythrocarpa was for the first time found in the flora of "Azas" Nature Reserve. New localities of alien species: Chenopodium ficifoilum, Galinsoga parviflora, Vicia hirsuta-were revealed.

В результате экспедиционных исследований, анализа ранее опубликованных работ и просмотра материалов, хранящихся в гербариях ЦСБС (NS, NSK) и государственного природного заповедника «Азас», уточнены сведения о видовом составе флоры бассейна Верхнего Енисея. Впервые во флоре Тывы отмечены Humulus lupulus, Atriplex hortensis, Saponaria officinalis, Raphanus sativus, Abutilon theophrastii, Cichorium intybus, Elodea canadensis, Cypripedium × ventricosum, Poa sergievskajae; во флоре Хакасии – Microcerasus tomentosa, Cypripedium × ventricosum, S. viridis subsp. pycnocoma; во флоре южной части Красноярского края – Microcerasus tomentosa, Cypripedium × ventricosum. Уточнено распростране- ние и обнаружены новые местонахождения редких на этой территории видов – Asterothamnus heteropappoides, Ulmus pumila, Saxifraga nivalis, Euphorbia caesia.