ITALIC 8.0

Arthonia medusula (Pers.) Nyl.

Mém. Soc. Imp. Sc. Nat. Cherbourg, 5: 132, 1857. Basionym: Opegrapha medusula Pers. - Ann. Wetter. Gesellsch. Ges. Naturk., 2: 15, 1810.

Synonyms:

Distribution: N - Ven. C - Laz.

Description: Thallus crustose, episubstratic, thin, whitish to yellowish white. Apothecia arthonioid, lirelliform, brown-black, semi-immersed in the thallus, 0.5-2 mm long, branched to stellate, with a mostly flat, grey-pruinose or rarely epruinose disc. Proper exciple poorly evident; epithecium blue-black, rarely dark olive-brown, K+ greenish; hymenium colourless to pale brown, 50-75 µm high, I+ blue; hypothecium colourless to pale yellowish. Asci 8-spored, broadly clavate, semi-fissitunicate, with a large apical dome and a distinct ocular chamber, Arthonia-type. Ascospores (2-)3(-4) septate, hyaline, more or less fusiform, 9-18 x 2-3 µm, the apical cell not enlarged. Pycnidia common, black but often white-pruinose, slightly emerging from thallus. Conidia bacilliform, 5-6 x 1-1.2 µm. Photobiont trentepohlioid. Spot tests: thallus K- or K+ yellowish, C-, KC-, P-. Chemistry: unidentified substances in thallus.

Note: a mild-temperate, suboceanic lichen found on old oaks, in dry parts of the trunks seldom wetted by rain, in parklands and open woodlands. The record from Veneto (see Nimis 1993: 80) requires confirmation. It is included in the Italian red list of epiphytic lichens as “Critically Endangered” (Nascimbene & al. 2013c).

Growth form: Crustose

Substrata: bark

Photobiont: Trentepohlia

Reproductive strategy: mainly sexual

Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)

In underhangs rarely wetted by rain

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: absent

Oromediterranean belt: absent

Montane belt: absent

Submediterranean belt: extremely rare

Padanian area: absent

Humid submediterranean belt: extremely rare

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

Herbarium samples

Index Fungorum GBIF

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste

Herbarium: TSB (5733)
2003/01/23

Elena Pittao; Owner: Department of Life Sciences, University of Trieste

Herbarium: TSB 5733

Elena Pittao; Owner: Department of Life Sciences, University of Trieste

Herbarium: TSB 5733

Redinger, K. (1938) Arthoniaceae, Graphidaceae . In Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. Band 9, 2 Abt., Part 1 (G. L. Rabenhorst, ed.): 181–404. Leipzig: Borntraeger