Arthonia melanophthalma Nyl.

Dufour ex Nyl., Mém. Soc. Sc. Nat. Cherbourg, 2: 336, 1854.
Synonyms: Arthonia coniangioides Bagl.
Distribution: C - Tosc, Laz, Sar (Rizzi & al. 2011, Di Nuzzo & al. 2022). S - Pugl, Cal (Puntillo 1996), Si (Grillo & Carfì 1997, Grillo & Caniglia 2004).
Description: Thallus crustose, thinly episubstratic, c. 40 μm thick, white to yellowish white, continuous and smooth or finely rimose, forming well-delimited, 1-2 cm wide, often confluent orbicular patches, without a distinct prothallus. Apothecia arthonioid, emarginate, black, epruinose, dull, semi-immersed in the thallus, rounded, ellipsoid or irregularly angular, 0.4-0.9 mm across. Proper exciple poorly developed, blackish; epithecium black, 7-10 μm high, K-; hymenium pale ochraceous yellow, 75-95 μm high, I+ blue; paraphysoids branched and anastomosing, very thin, with weakly swollen apical cells; hypothecium black to brown-black, wedge-shaped, 35-45 μm high. Asci 8-spored, broadly clavate, semi-fissitunicate, with a large apical dome and a distinct ocular chamber, Arthonia-type. Ascospores 3(-4)-septate, subclavate, with one of the apical cells slightly larger than the others, becoming slightly narrower toward the other end, hyaline, ellipsoid, 15-20 x 5-8 μm. Pycnidia rather frequent, black, somehow shiny. Conidia bacilliform, straight, 7-9 x c. 1 μm. Photobiont trentepohlioid. Spot tests: thallus K- or K+ pale yellow, C-, KC-, P-. Chemistry: unknown.
Note: a southern species in Europe, found on smooth bark in humid, coastal situations, most often with Dirina ceratoniae and Thelopsis isiaca, mostly Tyrrhenian in Italy.
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)
Taxon bound to maritime-coastal situations

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: very rare
Dry mediterranean belt: absent

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

Jennifer Fiorentino
Malta, Maltese Islands

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (24572)
isotype of Arthonia coniangioides Bagl.

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

Jennifer Fiorentino
Malta, Maltese Islands