EN
The paper presents a new site of Diphasiastrum zeilleri (Rouy) Holub in the Olkuska Upland within the Pomorzany forest administration region (50°17′42.06″N, 19°32′8.28″E). The discussed species is included on the Red List of Plants and Fungi in Poland (category V – vulnerable). In Poland, Diphasiastrum zeilleri is legally protected.The discovered population covers the area of 41 m2. The cover of live shoots within the population is 80%. Since 2005, the occurrence of sporophylls releasing the spores has been observed. The main threat to the population are silviculture treatments in the area of the species occurrence. In order to protect the described population of D. zeilleri, it has been agreed with the Olkusz Forest District Management to minimize the potential economic treatments in the immediate vicinity of the stand. This will prevent the exposure of the population to direct or indirect damage