The floristic researches of the Pacific Northwest and Northeast are being continued. The are focused on the determination of floral-genetic links of the largest terrestrial phyto-formations of Northern Asia and Northern America on the instance of northeastern - northwestern Pacific. The comparison of possible ways of the floras transformation with strengthening of human impact has been undertaken. Some of the preliminary results are the following. The large disjunction once formerly connected ranges of common or close related flora taxa for the Pacificís North East - North West are appear obvious with consideration the northern hemisphere flora multi-complex and are confirmed existing paleobotanical data. Especially that similarity is shown on instance of tertiary relicts, rare and endangered plant species and also the taxa which isolation and origination were furthered by transformations going on in Pleistocene. Ecological conditions and floristic compositions of the plant communities in habitat sites of common or close related species in the considered phyto-formations are not always identical. With anthropogenic impact the vector of quality composition recombination of similar local floras depends on series of factors. Among those current meso-climats and the levels of substrate multi- complex sustainability play the leading role. The changes of quality composition of close related floras in both regions caused by non-natural factors lead to origination of poor plants communities compositions with weak and unstable genetic potential and lose of natural floral-genetic links and similarities between studied regions as well.

Key words: endangered plant species, floral-genetic links, phyto-formation, Pleistocene, rare, tertiary relict