Diversity of yarrow species (Achillea L. - Asteraceae) in Priyeniseisky Sayan mountains

The data on diversity of yarrow (genus Achillea L.) of Prieniseisky Sayan Mountains including the south of Krasnoyarsk region, Khakassia and north-ern Tuva are presented in thisstudy. Until now about three species of yarrow were known: Achillea millefolium, Achillea asiatica and Achillea nobilis occurring in the area. As a result of inventory genus was supplemented by another four species: Achil-lea inundata, Achillea schmakovii, Achillea sergiev-skiana and Achillea setacea. In the process of in-vestigation there was a question about relationship between collected Achillea shmakovii and Achillea sergievskiana on one side and Achillea nigrescens described from Canada from the other side. A de-tailed comparison of the species diagnoses led to the conclusion that Achillea nigrescens was absent in the Prieniseisky Sayan Mountains (and probably in the South Siberia), being replaced by the related taxa. Research of herbarium materials showed that yarrows of the steppe and forest-steppe regions distinctly differed from widespread in the region Achillea asiatica and may be described as a new species: Achillea schauloi (locally spread in a low mountains steppe) and Achillea kuprijanovii (widely spread in a forest-steppe). Achillea kuprijanovii may be identified as previously described varieties of species Achillea asiatica var. marginata and var. intermedia. Another unusual giant yarrow observed in Krasnoyarsk forest-steppe since 1999, it was connected with birch and mixed forests and grew among high herbs and bracken. The research of plants in introduction and numerous finds in nature lead to the conclusion that giant yarrow may be de-scribed as a new species Achillea jenisseensis. As a result, it was found that yarrow diversity in Prieniseisky Sayan Mountains considering taxa earlier established for the region is ten species, most of which was very rare.