Taxonomy of Solorina bispora Nyl. ssp. bispora (Ascolichenes) based on spore wall ornamentation. Morphology and structure of spores of S. bispora Nyl. were investigated with light- and scanning electrone microscope to elucidate the taxonomy of its infraspecific taxa. A key for determination of all European taxa of the genus Solorina is also proposed. Keywords: lichens, Solorina bispora ssp. bispora, spores, wall ornamentation, scanning electron microscopy, taxonomy, key.