Acarospora intermedia H.Magn.

K. svenska Vetensk-Akad. Handl., n.f. 7, 4: 174, 1929
Distribution: N - VG, Lig (Knudsen & Kocourková 2020). C- Laz, Sar.
Description: Thallus crustose, episubstratic, areolate, pale to dark brown, epruinose. Areoles 0.5-1 mm in diam., 0.2-0.4 mm thick, round to irregular in shape, some of them slightly lobed and with a brown underside. Epicortex lacking; cortex 15-20(-30) μm thick, the upper layer dark brown, 5-10 μm thick, the lower layer brown or colourless, the cells mostly round, 2-4 μm across; algal layer continuous, not interrupted by hyphal bundles, 35-90 μm thick; medulla 75-90 μm thick, mixed with substrate crystals, white and opaque, the medullary hyphae thin-walled, 3-4 μm wide. Apothecia lecanorine, at first immersed, then becoming elevated above the areoles, the thalline margin sometimes darker or paler then the areoles, usually 1-4 per areole, less than 1 mm across, with a brown, round to irregular, often distinctly rugulose, epruinose disc, and a margin that sometimes is darker or paler then the areoles. Proper exciple thin, 5-15 μm wide or indistinct; epithecium dark brown, c. 10 μm high; hymenium colourless, (60-)90-100(-120) μm high, hemiamyloid, I+ blue turning reddish; paraphyses coherent, 1-2 μm thick at mid-level, the apical cells 2-4 μm wide; subhymenium 20-30 μm thick, hypothecium 5-10 μm thick or indistinct. Asci c. 100-spored, clavate, the apical dome K/I-. Ascospores 1-celled, hyaline, narrowly ellipsoid to (rarely) ellipsoid, 4-5 x c. 1.5(-2) μm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a lowland species of siliceous rocks in sunny situations; poorly developed samples with immersed apothecia are practically undistinguishable from A. veronensis.
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: very rare
Humid mediterranean belt: very rare
Dry mediterranean belt: extremely rare

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

Kerry Knudsen
Specimen collected by V. Golubkov, 1996 (GSU).