Acarospora rehmii H. Magn.

K. svenska Vetensk-Akad. Handl., ny föl. 7, 4: 185, 1929
Synonyms: Acarospora tongletii f. rehmii (H. Magn.) Clauzade & Cl. Roux
Distribution: N - VG (Magnusson 1936)..
Description: Thallus crustose, thinly episubstratic, more or less continuous or indistinctly areolate, for the largest part ecorticate, whitish, forming well-delimited, up to 6 cm wide, mostly orbicular patches. Areoles 0.5-0.9 mm wide, 0.2-0.3(0.4) mm thick, separated by rather indistinct cracks, concave to flat, often poorly evident. Cortex absent or visible as a 35-50 μm thick layer only at the very margins of the areoles; algal layer continuous; medulla poorly developed, filled with granules from the substratum. Apothecia cryptolecanorine, 0.2-0.6 mm across, at first immersed, then more or less emergent, round to angular, sometimes confluent, with a concave, brown disc and a prominent, entire margin. Proper exciple distinct, 10-15 μm wide; epithecium yellowish brown; hymenium colourless, (95-)100-120(-135) μm high; paraphyses 1.5-2 μm thick at base, the apical cells up to 3-μm wide; hypothecium colourless, K-. Asci 100-200-spored, clavate, the apical dome K/I-. Ascospores 1-celled, hyaline, ellipsoid to subcylindrical, 3-4.5 x 1.5-2 μm. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: This is a distinct species according to Knudsen & Kocourková (2020), differing from A. paupera in the absence of norstictic acid. It grows on calciferous sandstone below the montane belt, and it might be more widespread in Italy.
Growth form: Crustose
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: absent
Submediterranean belt: very rare
Padanian area: absent
Humid submediterranean belt: absent
Humid mediterranean belt: absent
Dry mediterranean belt: absent

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model