Acarospora modenensis H. Magn.

K. Svenska Vetensk.-Akad. Handl., ser. 3, 7, 4: 259, 1929.
Synonyms: Acarospora engadinensis H. Magn.?
Distribution: N - VG, Piem (TSB 33339), Emil (Fariselli & al. 2020), Lig. C - Tosc (TSB 34209), Sar. S - Camp (Nimis & Tretiach 2004).
Description: Thallus crustose, episubstratic, areolate, the areoles 0.3-1 mm wide, 0.3-0.4 mm thick, chestnut brown, dispersed or clustered, sometimes arranged in lines along cracks in the rock; lower surface whitish. Epinecral layer present, 5-15 µm thick; cortex paraplectenchymatous 20-40(-70) µm thick, underlain by a rather discontinuous, but not toothed algal layer. Apothecia lecanorine, 0.2-0.7 mm across, usually 1 per areole, rarely 2-4 per areole, occupying most of its surface, with a dark brown (darker than thllus), concave, sometimes umbonate disc, and an evident thalline margin of variable thickness. Epithecium brown; hymenium colourless, 65-90 µm high; paraphyses (1.5-)2-3 µm thick at base, the apical cells 3-5 µm wide; hypothecium colourless. Asci 100-200-spored, clavate, the apical dome K/I-. Ascospores 1-celled, hyaline, ellipsoid 3-6 x 1.5-2.5 µm. Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a mild-temperate species of siliceous rocks, often found on walls below the subalpine belt, probably overlooked and more widespread.
Growth form: Crustose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Pioneer species

Commonnes-rarity: (info)

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

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

P.L. Nimis CC BY-SA 04
TSB 20084

Magnusson A. H. (1935) Acarosporaceae, Thelocarpaceae. - In: Rabenhorst G. L.: Kryptogamen-Flora von Deutschland, Österreich, und der Schweiz-. 2nd- IX. Die Flechten. Abt. 5- 1. Gebr. Borntraeger. Leipzig, pp. 1-318. – Public Domain

P.L. Nimis CC BY-SA 4.0
TSB 29084