Acarospora epithallina H. Magn.

K. Svenska Vetensk.-Akad. Handl., ser. 3, 7, 4: 72, 1929.
Distribution: C - Sar. S - Si.
Description: Thallus crustose, episubstratic, consisting of a few, scattered to clustered, yellow to ochre-yellow, rounded to angular, strongly convex (but flattened or concave at top), 0.5-5 mm wide, 0.4-0.8 mm thick areoles developing on the thalli of Acarospora hilaris, rarely appearing autonomous due to the death of the host. Upper cortex 120-140 µm thick; algal layer uneven, interrupted by hyphal bundles; medulla white. Apothecia lecanorine-aspicilioid, 1-2(-4) per areole, at first punctiform, then expanded, round to elliptical in outline, 0.2-2 mm across, with a ochre-yellowish disc and a weakly prominent thalline margin. Epithecium yellowish; hymenium colourless 100-130 µm high, I+ blue turning reddish; paraphyses c. 2 µm thick at base, the apical cells hardly swollen; hypothecium colourless. Asci c. 100-spored, clavate, the apical dome K/I-. Ascospores 1-celled, hyaline, globose, 3-4 µm wide. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV+ orange. Chemistry: rhizocarpic acid.
Note: on steeply inclined, sunny surfaces of hard siliceous rocks, especially quartzite, on the thalli of A. hilaris. The species, reported from Macaronesia to Turkey, in Italy is much less frequent than its host, being restricted to the driest parts of the Mediterranean Region.
Growth form: Crustose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
In underhangs rarely wetted by rain
paras Acarospora hilaris

Commonnes-rarity: (info)

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

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (35719)
on the host, Acarospora hilaris

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (5178)