Image of rosette lichen

Description:

Slo.: ? - syn.: Parmelia stellaris f. aipolia (Ehrh. ex Humb.) Hazsl., Xanthoria aipolia (Ehrh. ex Humb.) Horw. - Habitat: abandoned pastures with scattered trees; moderately inclined mountain slope, south-east aspect; relatively warm and dry place; calcareous ground, sunny place; exposed to direct rain; average precipitations ~ 3.000 mm/year, average temperature 7-9 deg C, elevations 600 m (1.950 feet), alpine phytogeographical region. Substratum: bark of smaller branches of a stand-alone, recently cut down Juglans regia. Comment: When dry Physcia aipolia doesn't seem very attractive lichen. It is monotonously whitish-gray or gray and blends well with grayish bark of tree branches and twigs. However, when wet its bluish or greenish colors pop out distinctly. Its dark and almost always abundant apothecia pup out from much lighter thallus and its distinctive maculae (white spots on greenish thallus) become very apparent. Physcia aipolia is quite a common lichen and has been recorded in Slovenian Alps many times (Ref.: 6, 7, 8). It can be distinguished from several other similar Physcia species by distinctive maculae, yellow K reaction of thallus and medulla and pale lower side of the thallus having pale rhizines. It is mostly growing on small and medium size branches of smooth barked trees. Ref.: (1) C.W. Smith, et al, The lichens of Great Britain and Ireland, The British Lichen Society, (2009), p 700. (2) I.M. Brodo, S.D. Sharnoff, S. Sharnoff, Lichens of North America, Yale Uni. Press (2001), p 549. (3) V. Wirth, Die Flechten Baden-Wrttembergs, Teil.1. 2., Ulmer (1995), p xx. (4) F.S. Dobson, Lichens, The Richmonds Publishing Ca.LTD (2005), p 338. (5) https://www.123pilze.de/DreamHC/Download/Ziegen-Schwielenflechte.htm (accessed 1.2.2018) (6) Boletus Informaticus Database, Forestry Institute of Slovenia http://www.zdravgozd.si/bi_index.aspx (accessed 1.2.2018) (7) Prgger et all. 'Alphabetical list of lichenized fungi for the six phytogeographical regions of Slovenia', http://members.chello.at/johannes.pruegger/uni/slovenia/ (accessed 1.2.2018) (8) F. Bati, K. Primoi, B. Surina, T. Trot & H. Mayzhofer, Contributions to the lichen flora of Slovenia X. - Contributions to the lichen flora from the Slovenian Julian Alps, Herzogia 16, (2003): 143154