ITALIC 8.0

Acarospora helvetica H. Magn.

Svensk Bot. Tidskr., 18: 336, 1924.

Synonyms: Acarospora austriaca H. Magn.; Acarospora obscura H. Magn.

Distribution: N - Ven (Knudsen & Kocourková 2020). C - Sar (Knudsen & Kocourková 2020).

Description: Thallus crustose, episubstratic, areolate, the areoles angular to almost round, 0.2-1(-3) mm wide, contiguous and forming a rather well-delimited thallus, more rarely dispersed, sometimes the peripheral ones indistinctly lobulate, flat to slightly convex, usually dark brown to reddish brown with a darker margin, epruinose. Cortex 15-20(-30) µm thick, the upper part dark brown, the lower part colourless, without a distinct epicortex; algal layer continuous, 30-80 μm thick; medulla white, up to 300 μm thick, the hyphae 3-5 μm thick. Apothecia 0.2-0.5(-1) mm across, usually immersed, 1(-5) per areole, with a slightly concave to flat, smooth, brown to reddish brown disc, and a poorly evident to slightly raised thalline margin; proper margin forming a distinct parathecial ring in mature apothecia. Proper exciple at first thin, later expanding up to 100 μm above the disc; epithecium pale brown 10-15 μm high; hymenium colourless, 70-100(-120) μm high, the hymenial gel hemiamyloid, K/I+ light blue fading to light red; paraphyses 1.5-2 µm thick at mid-level, the apical cells up to 3 µm wide; subhymenium 20–30 μm high, IKI+ blue; hypothecium colourless, 10-20 high, IKI-. Asci 100-200-spored, clavate, the apical dome K/I-, 55-75 x 15-17μm. Ascospores 1-celled, hyaline, narrowly ellipsoid, 3-4(-5) x 1.5-1.7(-2) μm. Pycnidia rare. Conidia c. 2 x 0.5 μm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: thallus without lichen substances.

Note: on intermediate, base-rich siliceous rocks, from the submediterranean to the alpine belt; known from Central and Southern Europe. For further details see Knudsen & Kocourková (2020).

Growth form: Crustose

Substrata: rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

Pioneer species

Commonnes-rarity: (info)

Alpine belt: extremely rare

Subalpine belt: rare

Oromediterranean belt: absent

Montane belt: rare

Submediterranean belt: very rare

Padanian area: absent

Humid submediterranean belt: very rare

Humid mediterranean belt: absent

Dry mediterranean belt: extremely rare

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

Source: Knudsen K. & Kocourková J. (2020) Herzogia 33(1): 1-8

Austria.
). B. Thallus with apothecia (Poelt, GZU). C. Detail of the thallus with sharp edged areoles and immersed apothecia. – Scale bars: A, B = 1mm. C = 500 μm.

Lucia Muggia CC BY-SA 4.0; Owner: Department of Life Sciences, University of Trieste

Herbarium: GZU (327-81, 1981, Leg. J. Poelt)

Lucia Muggia CC BY-SA 4.0; Owner: Department of Life Sciences, University of Trieste

Herbarium: GZU (327-81, 1981, Leg. J. Poelt)

Lucia Muggia CC BY-SA 4.0; Owner: Department of Life Sciences, University of Trieste

Herbarium: GZU (327-81 Leg. J. Poelt)

Elena Pittao CC BY-SA 4.0; Owner: Department of Life Sciences, University of Trieste

Herbarium: TSB (11614)

Walter Obermayer - Source: Lichens of Noricum - http://lichens-of-noricum.uni-graz.at/

Stubalm-Speikkogel, Poelt 24.6.1973: