The presence of the fern species Anogramma leptophylla was detected in the Zempléni Mountains (NE Hungary) in 1991. The species was known neither from the country nor from the whole Carpatho-Pannonian Region (also known as Carpathian Basin) previously. Its habitat is situated on a roadside bank, cut into an unstable rhyolite surface, above the valley of the Creek Kemence near the village of Pálháza. The fern is a cosmopolitan taxon restricted to humid environments and is considered to be an oceanic-suboceanic (Atlantic) element in Europe. The occurrence in Hungary is located more than 1000 km from the closest populations, thus, this is one of the most remote inland occurrences of this (sub)oceanic species. This striking presence of the fern may be due to the peculiar microclimatological conditions of the habitat, which are described here in order to give an exact explanation for this outstanding occurrence. The chromosomes were also counted in some individuals of the Hungarian population and were found to be n = 26^II for each sample.