An occurrence of the ferns Notholaena marantae and Asplenium cuneifolium was revealed on the small ultrabasic picrite outcrops near the settlement Lety-Rovina in Bohemian Karst in Central Bohemia (49° 55’ 24.9” N; 14° 13’ 21.2” E).
The finding of both of species in the near vicinity of Prague in the botanically well-known area is surprising. However, their local populations are considered to be spontanneous and probably native due to the chemical and physical properties of the ultrabasic picrite rock and due to the history and contemporary vegetation cover of the habitat. N. marantae grows here on the northernmost locality of its distribution area (till present it has been known in the Czech Republic only from serpentinite rocks near Mohelno, southwestern Moravia). Rocky-steppe flora and vegetation of this place are shortly described. Both species N. marantae and A. cuneifolium have been recorded from the Czech Republic only from serpentine rocks till present. The fact, that they can grow on the other types of rock with similar chemical composition is discussed. Description of picrite chemistry is added (according to papers of F. Fiala). Determination of A. cuneifolium was confirmed using of the spore size indicating a diploid chromosome number.