Flora and vegetation of the Loppio lake (western Trentino, Italy). - The characteristics of the flora and the vegetation of the Loppio lake (western Trentino, Italy) are presented. The study point out the variation in species composition of the flora and vegetation after the lake was drying up in 1958; in fact 25 species of the 129 present before are desappeared and particularly are desappeared all hydrophytes.