Rare species of meadow plant communities in the valley of the lower stream of the Ussury river

The article offers the research of rare species state in the valley of the Ussury River lower stream; they belong to the following populations of meadow communities: Lychnis fulgens Fisch., Paeonia lactiflora Pall., Platycodon grandiflorus (Jacq.) A. DС., Potentilla freyniana Bornm, and Trommsdorffia ciliata (Thunb.) Sojak. The paper presents characteristics of these rare species habitat and structure of the meadow plant communities. For each species, the author cites the data on the number of individuals in populations, ecological density and vitality, as well as the data on morphometric parameters of individuals, which allows an assessment of the species cenopopulations state. The author has identified the limiting factors and worked out the measures aimed at these rare species protection.