Heterocladium dimorphum (Heterocladiaceae, Bryophyta) – an old element of the Hungarian bryophyte flora rediscovered

Heterocladium dimorphum is considered to be a data-defi cient moss species that has been neither collected nor observed in the last 46 years in Hungary. During the systematic fi eld studies aimed at exploring the recent bryophyte fl ora of the Kőszeg Mts and in the framework of grid-cell based bryophyte recording, H. dimorphum was discovered in two new locations of the Kőszeg Mts and re-found in one of the old locations in the Visegrád Mts. Th e size of populations is estimated and the habitats are characterized. Illustrations and a short description of the species are provided. Th e previous occurrences of H. dimorphum in Hungary are listed based on the specimens of the bryophyte collection of the Hungarian Natural History Museum, Budapest (BP). Based on the extant populations, the species is considered as endangered (EN)