Resultsof research on chorological, ecological and coenotic characteristics of an alien species of North American origin -Grindelia squarrosa (Pursh) Dunal (Asteraceae)in Chernivtsi region (Ukraine) are presented. The species was found in the region in three associations of synanthropic vegetation, such as the Convolvulo-Agropyretum repentis Felföldy 1943 and Ambrosio artemisiifoliae-Grindelietum squarrosae Smetana, Derpoluk, Krasоva 1997 of the class Artemisietea vulgaris Lohmeyer et al. in Tx. ex von Rochow 1951, Lolio-Plantaginetum majoris (Linkola 1921) Beger of the class Polygono-Poеtea annuae Rivas-Mart. 1975 and association of Setario pumilae-Echinochloetum cruris-galli Felföldy 1942 corr. Mucina in Mucina et al. 1993 of the class Digitario sanguinalis-Eragrostietea minoris Mucina, Lososová et Šilc in Mucina et al. 2016). The indices of main edaphic and climatic factors for the species were determined for the first time. According to the main climatic indices, such as thermo-, ombro-, and cryoregime, the species G. squarrosa is characterized by stenotopic amplitude and belongs to submezotherms, subaridophytes, and hemicryophytes. The map of distribution of the species in the region is presented

At the results of investigation of micromorphology features of seed surface of the Portulaca oleracea aggr. (Portulacaceae Juss.) from Chernivtsi Region (Ukraine) six morphotypes of this taxa were recorded. Some peculiarities of the seed morphology of Portulaca L., and features of the ultrastructure of seed surface of the P. oleracea aggr. morphotypes, based on the results of micromorphological studies with using electronic scanning microscope was described. The general for the representative of the genus (e.g. globous, ovate or almost reniform shaped of seeds; black or dark brown color) and specify for the morphological types (star-shaped, isodiametric or elongate cells of seed surface with central part and long or short rays; smooth surface of seed or with knobs (from 0,03 mm in diameter) or papillae (0,01–0,02 mm), etc.) peculiarities are determined. The original scanning electron microscopy (SEM) photographs of seed surface ultrastructure of the studied morphological types and key fragment for its determination are suggested. According to our investigation six morphotypes of Portulaca oleracea aggr. are presented in Chernivtsi Region. Some of them are new for studied territory (P. granulatostellulata (Poelln.) Ricceri & Arrigoni, P. papillatostellulata (Danin & H.G. Baker) Danin), and other (Portulaca nitida (Danin & H.G. Baker) Ricceri & Arrigoni, P. trituberculata Danin, Domina & Raimondo, P. tuberculata (Danin & H.G. Baker) Danin) – new floristic records for Ukraine, and one of them (P. oleracea) – was known before also. The maps of distribution of this morphotypes in the region are presented. At the results of morphotypes distribution the most common is P. granulatostellulata and P. oleracea – rare in studied region like as in Europe also.

The results of an investigation of alien species that change the character, condition, form or nature of ecosystems over large areas (transformer species) in the flora of the Starobilsk grass-meadow steppe are presented. The check-list of alien plants includes over 386 species of vascular plants, of which 28 are invasive and 6 are transformer species. In this study, the data on the first records of alien species, their distribution history, ecology, occurrence in different plant communities and degree of naturalization were compiled. The distribution maps of transformer species are provided.