Image of wart lichen

Description:

Very uncertain determination. According to Wirth (1995) this is the only amphibious Verrucaria on calcareous rock. But, it is not listed in Pruegger et all., Catalogue of lichenized and lichenicolous fungi of Slovenia for NW Slovenia (alpine phytogeographical region). On the other hand, The Information System on Italian Lichens, http://dbiodbs.univ.trieste.it/askita1.html shows its distribution in extreme NE Italy, a region just bordering Posocje having similar habitats. It may not be Verrucaria at all. Ref: V.Wirth, Die Flechten Baden-Wuerttembergs, Ulmer (1995), Vol. 2, p965 Habitat: cold mountain stream shore, partly shady in a narrow alpine valley, humid air, exposed to rain and sun (a few hours a day only), precipitations ~3.000 mm/year, average temperature 7-9 deg C, elevation 470 m (1.550 feet), alpine phytogeographical region. Substratum: submerged, occasionally dry small calcareous boulder of about 25 cm diameter.