Station of Microbryum davallianum (Pottiaceae) in the Lublin Upland. Microbryum davallianum (Sm.) R.H.Zander is a moss growing in the lowland of Poland. The number of its localities is estimated at over 70, the vast majority of them from the 19th century and the first half of the 20th century. Recently, Rusińska & Górski (2012) gave several stations of this species from the vicinity of Poznań, revising the available herbarium materials and presenting its occurrence in the country. It is unknown what factors are behind the rarity of M. davallianum in Poland. The current situation of this moss indicates that it should be considered an endangered species, mainly due to the significant decrease in the number of its stations. The paper describes a new station discovered on 27 June 2018 in Białobrzegi near Zamość in the Lublin Upland (50°45′24″N, 23°8′50″E, leg. R. Krawczyk, LBL, SOSN). The plant inhabited the periodically flooded and plowed margins of a mid-field depression, profusely producing sporophytes.