Image of protoblastenia lichen

Description:

Slo.: ? - syn.: Callopisma rupestre f. incrustans (DC.) Walt. Watson, Caloplaca incrustans (DC.) Flagey, Lecanora incrustans (DC.) Ach., Lecidea incrustans (DC.) Chevall., Lecidea incrustans (DC.) Chevall. - Habitat: man made stone wall delimiting former pastures now partly overgrown with bushes and trees; slightly inclined mountain slope, southeast aspect; calcareous ground; partly in shade; relatively dry and warm place; partly protected from direct rain by tree canopies; average precipitations ~ 3.000 mm/year, average temperature 7-9 deg C, elevations 580 m (1.900 feet), alpine phytogeographical region. - Substratum: +/- vertical hard calcareous rock surface. - Comment: Genus Protoblastenia is comprised by lichens living on rock (saxicolous). Their thallus is crustose or grows within solid rock (endolithic) or it is something in between these two options. These lichens have usually yellow, orange or red apothecia and simple cell spores (Ref.:3). Their similarity to Caloplaca species on macroscopic level causes frequent confusions. However, Caloplaca species have two celled spores (septate spores), which distinguish them from Protoblastenia species with certainty. - Protoblastenia incrustans is a common lichen, but it is certainly many times overlooked. Namely, thallus is usually endolithic and consequently hard to be seen. Its apothecia are very small, from only 200 to 500 microns in diameter (Ref.:3) and can also hardly be seen by naked eye in spite of the fact that they are bright yellow-orange color. Characteristically, its apothecia sit in small pits in the rock. Their surface is from slightly concave to slightly convex shape, most of them are nearly flat. This species is an arctic-alpine element (Ref.:5). - Ref.: (1) F.S. Dobson, Lichens, The Richmonds Publishing Ca.LTD (2005), p 364. (2) http://www.dorsetnature.co.uk/pages-lichen/lch-387.html (accessed 28.2.2018) (3) C.W.Smith, et all, The lichens of Great Britain and Ireland,The British Lichen Society,(2009), p 750. (4) V. Wirth, Die Flechten Baden-Wrttembergs, Teil. 2., Ulmer (1995), p 773. (5) I.M. Brodo, S.D. Sharnoff, S.Sharnoff, Lichens of North America, Yale Uni. Press (2001), p 586.