ITALIC 8.0

Acarospora pyrenopsoides H. Magn.

Acta Horti Götoburg., 2: 74, 1926.

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Distribution:

Description: Thallus crustose, episubstratic, of clustered or contiguous, 1.5-2.5 mm wide, convex to bullate areoles, the upper surface flattened, dark brownish grey, epruinose or rarely partially pruinose, sometimes minutely rugulose (noticeable when wetted), the margins with steep, jet black flanks. Lower surface blackish brown. Epicortex lacking or <10 μm thick; cortex very thin, poorly delimited, 8-15 μm thick, the pigmented layer often one cell thick, the lower layer colourless; algal layer uninterrupted by hyphal bundles; medulla white. Apothecia mostly 2-8 per areole, round, 0.1-0.7 mm across, at first deeply immersed, then level with thallus, with a dark brown, somehow glossy, epruinose, smooth to uneven disc and a raised, persistent proper margin. Proper exciple 15-20 µm wide laterally, increasing upward to 35-50 µm; epithecium dark brown; hymenium colourless, (120-)130-150(-170) μm high, the hymenial gel eumyloid, I+ persistently blue; paraphyses (1-)1.5(-2) μm wide at mid-level, the apical cells swollen, up to 3 µm wide; subhymenium 20-30 μm high, I+ blue; hypothecium grey. Asci (100-)200-spored, cylindrical to narrowly clavate. Ascospores 1-celled, hyaline, narrowly ellipsoid to subcylindrical, 4-5 x 1.5(-2) μm, Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.

Note: a rather poorly known species described from Greenland; the ecology is poorly known as well, but the species usually occurs on steep faces and under overhangs of siliceous rocks; known from a few localities in the Alps, from France to Austria. To be looked for in the Italian Alps. For further details see Westberg & al. (2015) and Roux & al. (2019).

Growth form: Crustose

Substrata: rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

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Poleotolerance:

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Altitudinal distribution:

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Predictive model

Source: Westberg M, Timdal E, Asplund J, Bendiksby M, Haugan R, Jonsson F, Larsson P, Odelvik G, Wedin M, Millanes AM (2015) New records of lichenized and lichenicolous fungi in Scandinavia. MycoKeys 11: 33-61. - CC BY-4.0

NORWAY. Aust-Agder: Valle, Hallandsfossen. 28 July 2010, Timdal 11308 (O L-163369)
Scale: 1 mm.

Source: Magnusson A.H. 1935. The lichen-genus Acarospora in Greenland and Spitsbergen Meddelelse No 27

Scale bar: 1 mm