Arthonia varians (Davies) Nyl.

Lichenes Scand.: 260, 1861. Basionym: Lichen varians Davies - Trans. Linn. Soc. London, Bot., 2: 284, 1794.
Synonyms: Celidium sordidum Anzi; Celidium varians (Davies) Arnold
Distribution: N - Frl (Tretiach & Hafellner 2000, Brackel 2016), Ven (Brackel 2016), TAA (Brackel 2016), Lomb (Brackel 2016), Piem (TSB 33690), VA, Emil (Tretiach & al. 2008, Brackel 2016), Lig (Brunialti & al. 1999). C - Tosc (Brackel 2016), Marc (Nimis & Tretiach 1999), Umb (Panfili 2000, Ravera & al. 2006), Laz (Brackel 2016), Mol (Nimis & Tretiach 1999, Brackel 2016), Sar (Rizzi & al. 2011, Giordani & al. 2013, Brackel 2016). S - Camp (Brackel 2016), Pugl (Brackel 2016), Bas (Nimis & Tretiach 1999, Brackel 2016), Cal (Puntillo 1996, Brackel & Puntillo 2016, Brackel 2016), Si (Ottonello & al. 1994, Brackel 2008b, 2008c, 2016).
Description: Thallus inapparent, not lichenized, the hyphae developing inside the apothecial discs of species of the Lecanora rupicola- complex. Apothecia arthonioid, developing in the hymenium of the host and blackening the disc, 0.3-1 mm across, with a flat to slightly convex disc, without a proper margin. Exciple poorly developed, not evident; epithecium brown to olive-brown, K+ pale green; hymenium colourless, 45-60 μm high, I+ blue; pseudoparaphyses 1.5-2(-2.5) μm thick, the apices with a brown cap; hypothecium colourless. Asci 8-spored, broadly clavate to subglobose, semi-fissitunicate, with a large, non-amyloid apical dome, and a distinct ocular chamber, Arthonia-type. Ascospores (1-)2-3-septate, hyaline, ovoid to narrowly ellipsoid, sometimes subclavate, 11-17 x 5-6.5 μm, rather thick-walled, without an epispore. Photobiont absent. Spot tests: K-, C-, KC-, P-. Chemistry: no lichen substances.
Note: a holarctic lichenicolous fungus with a wide altitudinal and latitudinal range, occurring throughout the country wherever the host is present; it parasitizes the hymenium of the host.
Growth form: Lichenicolous fungus
Substrata: rocks
Reproductive strategy: mainly sexual
paras Lecanora rupicola s.lat.

Commonnes-rarity: (info)

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


pH of the substrata:

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Solar irradiation:

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Aridity:

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Eutrophication:

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Poleotolerance:

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Altitudinal distribution:

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Manilio Prignano; Owner: Manilio Prignano
Italy, Abruzzo, Monti della Laga
2010


P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (34343)
2002/01/07
in the apothecia of the host, Lecanora rupicola


Manilio Prignano; Owner: Manilio Prignano
Italy, Abruzzo, Monti della Laga
2010


Manilio Prignano; Owner: Manilio Prignano
Italy, Abruzzo, Monti della Laga
2010


Manilio Prignano; Owner: Manilio Prignano
Italy, Abruzzo, Monti della Laga
2010


Manilio Prignano; Owner: Manilio Prignano
Italy, Abruzzo, Monti della Laga
2010


Manilio Prignano; Owner: Manilio Prignano
Italy, Abruzzo, Monti della Laga
2010


Domenico Puntillo; Owner: Domenico Puntillo
Italy


Leif Stridvall - Source: http://www.stridvall.se/la/galleries.php (Courtesy: Anita Stridvall)