Rarities from the xerothermic flora of eastern Austria: rediscoveries of four bryophyte species supposedly extinct in Austria

In the Austrian part of the Thayatal National Park, the following species, previously considered extinct, have been recovered: Pyramidula tetragona (Brid.) Brid., Cephaloziella stellulifera (Taylor ex Spruce) Schiffn., Oxymitria in-crassata (Bread.) Sergio & Sim-Sim and Riccia papillosa Moris. The last records of C. stellulifera and P. tetragona in Austria date back to the 19th century, those of O. incrassata and R. papillosa to the middle of the last century. The current habitats of all four species were hot, natural dry grasslands over gneissic rocks or calcareous schists.