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Syntaxonomic diversity of the vegetation in the southern tundra subzone of the Tazovsky Peninsula is represented by six associations, three subassociations and three variants. Four associations (Dicrano maji–Salicetum lanatae Khitun ass. nov. hoc loco, Sphagno girgensohnii–Betuletum nanae Khitun ass. nov. hoc loco, Empetro subholarctici– Eriophoretum vaginati Khitun ass. nov. hoc loco, Eriophoro leiocarpi–Caricetum rotundatae Khitun ass. nov. hoc loco), the three subassociations (Hierochloo alpinae– Hylocomietum splendentis empetretosum subholarctici Khitun subass. nov. hoc loco, Eriophoro leiocarpi–Caricetum rotundatae typicum Khitun subass. nov. hoc loco, Eriophoro leiocarpi–Caricetum rotundatae caricetosum chordorrhizae Khitun subass. nov. hoc loco) and the three variants are described for the first time. A high degree of similarity was found between vegetation of the Tazovsky Peninsula and vegetation of the southern part of the Gydansky Peninsula (the typical tundra subzone). They have four of six associations in common, whereas with the northern part of the typical tundra there is only one association in common.

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The syntaxonomic diversity of vegetation of two localities in the southern part of the typical tundra subzone in the Gydansky Peninsula includes seven associations, three subassociations and eight variants. New associations (Tanaceto bipinnati–Salicetum polaris Khitun ass. nov. hoc loco, Calliergono cordifolii–Salicetum lanatae Khitun ass. nov. hoc loco), subassociations (Hierochloo alpinae–Hylocomietum splendentis asahinetosumchrysantae Khitun subass. nov. hoc loco, Carici rariflorae–Sphagnetum baltici sphagnetosum steerei Khitun subass. nov. hoc loco) and eight variants are described in this region for the first time. Although in the northern part of the typical tundra subzone they occupy zonal positions, dwarf shrub communities with abundant herbs (Luzula tundricolae–Hylocomietum splendentis Telyatnikov et al. 2019) were not found in the studied locations. Tussock tundra (Sphagno–Eriophoretum vaginati typicum) occupies flat or gently sloping hills, and we consider it as the predominant zonal vegetation. The position of the boundary between the southern and the typical tundra subzones is corrected. According to our observations, it lies further north (up to 100 km on the eastern part of the peninsula) than it was shown on previous zoning schemes. Comparison of the syntaxonomic diversity in the southern and northern parts of the typical tundra showed little similarity, only two associations are common (Hierochloo alpinae–Hylocomietum splendentis Telyatnikov et al. 2019 and Tripleurospermo hookerii–Poetum alpigenae Czerosov, Sleptsova et Mironova 2005). We explain this by differences in local lithology: loams were predominant in the northern part and sands dominated in the southern part.

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