Mire ecosystems occupy circa 30% Karelian Republic mires. The diversity of mire plant cover is high. The mire flora includes 300 species of vascular plants and 133 species of mosses. The mire flora of Karelia, Finland and North-West Russia is compared. Many species of mire plants are rare and protected. The topological and ecological classification of mire vegetation is developed. Totally there are 55 associations and 4 classes of mire vegetation in Karelia. The main classification
techniques are compared.