Image of protoblastenia lichen

Description:

Slo.: ? - syn.: Blastenia rupestris var. calva (Dicks.) Lettau, Lecanora calva (Dicks.) Nyl., Protoblastenia rupestris var. calva (Dicks.) J. Steiner, Lecidea calva (Dicks.) Nyl. - Habitat: man made stone wall delimiting former pastures, which are partly overgrown with bushes and trees now; 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: Protoblastenia calva is not a rare species, however, as almost all endolithic lichens (their thallus is living inside rock among rock grains) is hard to spot from far. This is particularly true if they aren't fertile and dry. They appear as (usually only slightly) 'discolored' rock surface. When wet and fertile they are more apparent since colors are more pronounced. Protoblastenia calva possesses relatively large apothecia (up to 1.5 mm in diameter) of frequently vivid orange color. So, it can be spotted also by naked eye with some attention. Apothecia scattered, sessile, not in pits and from 0,5 to 1,2 mm in diameter, bullate or almost spherical. Thallus endolithic but not completely. Epilithic part white, surface farinous or very finely grainy (Wirth, 1995 - see pic.:10b). Fund on several places of several rocks, almost always right next to Protoblastenia incrustans (small yellow-orange apothecia in pits). Note also slightly darker thallus of Protoblastenia incrustans. Lichens photographed in moist conditions after several rainy days. Ref.: (1) F.S. Dobson, Lichens, The Richmonds Publishing Ca.LTD (2005), p 363. (2) http://dryades.units.it/italic/index.php?procedure=images2&taxon=Protoblastenia%20calva%20(Dicks.)%20Zahlbr%2E (accessed Feb. 25. 2018) (3) http://www.stridvall.se/lichens/gallery/Protoblastenia?page=1 (accessed Feb. 27. 2018) (4) http://www.stridvall.se/lichens/gallery/Protoblastenia/NIKA9793 (accessed Feb. 28. 2018) (5) C.W.Smith, et all, The lichens of Great Britain and Ireland,The British Lichen Society,(2009), p 750. (6) V. Wirth, Die Flechten Baden-Wrttembergs, Teil. 2., Ulmer (1995), p 773.