Acarospora fusca B. de Lesd.

Rec. Lich. Dunkerque, 1, Suppl.: 100, 1914
Synonyms: Acarospora anomala H. Magn.
Distribution: N - TAA (Nascimbene & al. 2007b).
Description: Thallus crustose, episubstratic, minutely areolate, without a distinct prothallus, forming patches of 1 cm or less. Areoles 0.2-0.9(-1.5) mm wide, 0,2.0,4 mm thick, contiguous, rounded to irregular, flat to usually slightly convex, deep brown to pale reddish brown, pale and ecorticate in lower part, epruinose. Epicortex lacking or <10 μm thick; cortex (10-)40-60 μm thick, the brown upper layer c. 10 μm thick, the lower layer colourless; algal layer 50-100 μm thick, even, continuous or rarely interrupted by <10 μm wide hyphal bundles, continuous beneath apothecia; medulla 100-250 μm thick, mixed with substrate particles. Apothecia lecanorine, 0.1-0.25(-0.6) mm across, rounded, 1-3(-4) per areole, immersed, with a reddish brown to dark brown, epruinose, usually flat, smooth or rough disc, and a usually paler brown, raised, smooth margin, the disc tending to become pseudogyrose when old. Proper exciple indistinct or expanding up to 60 μm around the disc, often forming an elevated margin concolorous with thallus; epithecium yellowish brown, c. 10 µm high; hymenium colourless, (85-)100-140(-160) µm high, hemiamyloid; paraphyses 1-1.7 µm thick at mid-level, the apical cells cylindrical to clavate and up to 2.5 μm wide; hypothecium colourless, (20-)40-55 µm high, K/I+ blue. Asci 100-200-spored, clavate, the apical dome K/I-. Ascospores 1-celled, hyaline, narrowly ellipsoid to bacilliform, 3-5(-6) x (1-)1.5-1.7(-2) µm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a poorly known species of eutrophicated, dry and hard lignum, closely related to, and possibly a synonym of other saxicolous species of the A. nitrophila-complex, hitherto reported from Scandinavia and the Alps. For further details see Knudsen & al. (2021, 2021b). A dubious record from Campania by Garofalo & al. (1999) is not accepted here.
Growth form: Crustose
Substrata: lignum
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Poorly known taxon in need of further study

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: extremely rare
Oromediterranean belt: absent
Montane belt: extremely rare
Submediterranean belt: absent
Padanian area: absent
Humid submediterranean belt: absent
Humid mediterranean belt: absent
Dry mediterranean belt: absent

pH of the substrata:

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Solar irradiation:

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Aridity:

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Eutrophication:

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Poleotolerance:

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Altitudinal distribution:

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Predictive model

Natural History Museum London - Source: https://mycoportal.org/portal/taxa/index.php?taxon=83801


Natural History Museum London - Source: https://mycoportal.org/portal/taxa/index.php?taxon=83801