Distribution of Caulinia minor (All.) Coss. et Germ. (Hydrocharitaceae) in Nizhny Novgorod Oblast

— The distribution of Calluna minor in Nizhny Novgorod oblast is described on the basis of published sources, herbaria, and original data. This species prefers water bodies with well-warmed shallow areas and high mineralization. This species should be included in the regional Red Data Book due to its location at the edge of its distribution. It is advisable to increase the rarity level of this species in the region. Recommendations on its conservation are proposed.