ITALIC 8.0

Acarospora cinerascens J. Steiner

in Arnold, Lich. Exs.: nr. 1500, 1890.

Synonyms: Acarospora alboatra H. Magn.

Distribution: N - TAA (Knudsen & al. 2015), VA (Piervittori & Isocrono 1999, Knudsen & al. 2015).

Description: Thallus crustose, episubstratic, areolate-subsquamulose, densely white-pruinose, the areoles 0.5-1(-2) mm wide, 0.3-0.6 mm thick, at first flat, then convex and fissured or reticulately grooved, dispersed or usually contiguous and separated by deep fissures, reddish brown, but almost always appearing white due to a thick layer of pruina, the margin most often dark. Epicortex to 30 µm thick, with small crystals dissolving in K; cortex 20-70 µm thick, brown in upper part, colourless in lower part, the cells mostly 3-4 µm wide; algal layer continuous, 100-150 µm thick; medulla white, to 0.4 µm thick, I-. Apothecia lecanorine, immersed, 0.3-1 mm across, with a black to brown-black sometimes slightly pruinose disc and a thick, often radially fissured thalline margin. Proper exciple prosoplectenchymatous, widening around the disc to c. 30-50(-100) µm, sometimes distinct as a blackish ring around the disc, I-; epithecium brown, c. 10 µm high; hymenium colourless, (80-)120-150 µm high, the hymenial gel hemiamyloid, K/I+ light blue fading to light red; paraphyses 1-3 µm thick, the apical cells hardly swollen; subhymenium 30-50 µm high, I+ blue; hypothecium narrow, usually 10 µm high. Asci 100-200-spored, clavate, the apical dome K/I-, 100-130 x 20-25 µm. Ascospores 1-celled, hyaline, ellipsoid, 6-9(-12) x 2.5-3.5(-4) µm. Pycnidia immersed, dark. Conidia simple, ellipsoid, c. 2 x 1.5 µm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances. 30–50 µm high, I+ blue; hypothecium narrow, usually 10 µm high. Asci 100-200-spored, clavate, the apical dome K/I-, 100–130 x 20-25 µm. Ascospores 1-celled, hyaline, ellipsoid, 6-9(-12) x 2.5-3.5(-4) µm. Pycnidia immersed, dark. Conidia simple, ellipsoid, c. 2 x 1.5 µm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.

Note: on weathered base-rich siliceous rocks, restricted to dry-warm Alpine valleys with a continental climate. Superficially similar to A. versicolor, but a different species (Knudsen & al. 2015).

Growth form: Crustose

Substrata: rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: very rare

Oromediterranean belt: absent

Montane belt: very rare

Submediterranean belt: extremely rare

Padanian area: absent

Humid submediterranean belt: absent

Humid mediterranean belt: absent

Dry mediterranean belt: absent

pH of the substrata:

1

2

3

4

5

(info)

Solar irradiation:

1

2

3

4

5

(info)

Aridity:

1

2

3

4

5

(info)

Eutrophication:

1

2

3

4

5

(info)

Poleotolerance:

0

1

2

3

(info)

Altitudinal distribution:

1

2

3

4

5

6

(info)

Predictive model

Index Fungorum GBIF

From: Knudsen et al., Herziogia, 28, 2: 690-696, 2015 (Buschardt 420 - B) Scale: 0.5 mm