Image of Frost Lichen

Description:

Slo.: ? - syn.: Physconia pulverulacea Moberg. Lichen distortus With. - Habitat: tree hedge between abandoned pastures; 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 medium and small size branches of (almost) stand-alone, recently cut down Juglans regia. - Comment: Physconia distorta is a widespread and common foliose lichen growing almost on the whole world. After longer rains, when it is soaked with rain it is deep green and beautiful, while when dry, it is dark brown, brown-grayish or gray and much less attractive. The species can be recognized by: usually abundant apothecia (see Pic.3), thallus without soralia, soredia, maculae or cilia and abundant black, bottle-brush-like rhizines (see Pic.10) forming a dense mat on the underside of the thallus (see Pic.8). Thallus underside is dark in older parts but much lighter toward the edges and rhizines are almost simple on the thallus margins.The upper canopy branches of the tree examined were full of specimens of this species. Pictures taken after several rainy days, except Pic.9 and 17, which show dry specimen.Ref.:(1) V. Wirth, R. Dll, Farbatlas Flechten und Moose, Ulmer, (2000), p 86.(2) V. Wirth, Die Flechten Baden-Wrttembergs, Teil. 2., Ulmer (1995), p 728.(3) F.S. Dobson, Lichens, The Richmonds Publishing Ca.LTD (2005), p 343.(4) C.W.Smith, et all, The lichens of Great Britain and Ireland,The British Lichen Society (2009), p 704.