Acarospora irregularis H. Magn.

K. Svenska Vetensk.-Akad. Handl., ser. 3, 7, 4: 229, 1929.
Synonyms: Acarospora badiofusca subsp. badiorubra Clauzade & Cl. Roux
Distribution: N - Frl, VA (Matteucci & al. 2013, 2015c). C - Tosc (Tretiach & al. 2008), Sar (Knudsen & al. 2014). S - Bas (Nascimbene & al. 2021), Si.
Description: Thallus crustose, episubstratic, areolate-subsquamulose, brown or reddish brown. Areoles 0.4-3 mm wide, 0.5-1 mm thick, substipitate and distinctly raised from the substrate, usually contiguous, flat to convex, round to angular, with an uneven surface; lower surface brown to reddish brown, sometimes whitish or blackened. Epicortex 10-40 μm thick; cortex (30-)40-60 μm thick, paraplectenchymatous, the cells c. 3-4 μm wide, the upper layer brown, the lower layer hyaline or golden; algal layer up to 200 thick, thinner beneath apothecia, uneven, with algal palisades interrupted by c. 40-50 μm wide hyphal bundles which are continuous with medulla; medulla 100-300 μm thick or more. Apothecia round, 0.5-2 mm across, immersed in the areoles, usually 1 per areole (sometimes 2-3 and confluent into larger clusters), with a reddish brown to black (reddish when wet), epruinose, flat to slightly convex, more or less smooth disc and a raised, thin margin concolorous with thallus or blackened. Proper exciple prosoplectenchymatous, up to 100 μm thick in upper part; epithecium brown, c. 15 μm high; hymenium colourless, (80-)100-120(-140) μm high; paraphyses 2-3 μm thick at base, sometimes expanded at apices; hypothecium colourless. Asci 100-200-spored, clavate, the apical dome K/I-. Ascospores 1-celled, hyaline, ellipsoid to broadly ellipsoid, (3-)3-5.3 x (1.5-)2-3 μm. Pycnidia oval to globose, visible as dark or reddish dots. Conidia simple, hyaline, c. 2 x μm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a species known from central Europe (Czech Republic, Hungary and Slovakia), as well as Austria, Greece and Italy, which was often confused with A. nitrophila and related species. According to Knudsen (2021), A. badiofusca subsp. badiorubra Clauzade & Cl. Roux is a synonym of this species.
Growth form: Squamulose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

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

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

P.L. Nimis CC BY-SA 4.0
TSB 35091

Source: Knudsen K. & al. 2014. The Bryologist, 117(4):319-328.
J. Kocourkova´ nr. 8286, Hb. Knudsen & Kocourkova

Source: Knudsen K. & al. 2014. The Bryologist, 117(4):319-328.
J. Kocourkova´ nr. 8286, Hb. Knudsen & Kocourkova

Source: Knudsen K. & al. 2014. The Bryologist, 117(4):319-328.
J. Kocourkova´ nr. 8364, Hb. Knudsen & Kocourkova