Arthonia galactinaria Leight.

Lich.-Fl. Great Brit., 3rd ed.: 426, 1879.
Distribution: N - TAA (Brackel 2015, 2016). C - Tosc (Brackel 2015, 2016), Abr (Brackel 2015, 2016, Gheza & al. 2021). S - Pugl (Brackel 2015, 2016), Si (Brackel 2008c, 2016).
Description: Thallus inapparent, not lichenized, forming discoloured patches on the apothecia of Myriolecis-species. Apothecia arthonioid, black, epruinose, convex and cushion-like, irregularly rounded, 0.1-0.2 mm across. Proper exciple very poorly developed; epithecium brown, K-, I+ rust-red, K/I+ blue; hymenium colourless, I+ red, K/I+ blue; paraphysoids branched and anastomosing, the apical cells swollen; hypothecium colourless. Asci (4-)8-spored, broadly clavate, semi-fissitunicate, with a large apical dome and a distinct ocular chamber, Arthonia-type. Ascospores 1-septate, with a cell wider and longer than the other, not or only slightly constricted at septum, at first hyaline but soon turning pale brown, soleiform, 9-13 x 4-5 μm, smooth-walled. Photobiont absent. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: this lichenicolous fungus is widespread and quite common in Europe and is also known from Asia, North America, northern Africa, and New Zealand. It seems to be restricted to Myriolecis-species, especially M. dispersa, whereas the very similar Arthonia lecanorina grows on Lecanora albella. Collections of Arthonia clemens (which is restricted to Rhizoplaca) on epilithic Lecanora species were reported from several localities in Italy; they may belong to A. galactinaria or to A. apotheciorum, which grows on Myriolecis albescens.
Growth form: Lichenicolous fungus
Substrata: rocks
Reproductive strategy: mainly sexual
paras Myriolecis spp.

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: absent
Oromediterranean belt: absent
Montane belt: rare
Submediterranean belt: rare
Padanian area: absent
Humid submediterranean belt: rare
Humid mediterranean belt: rare
Dry mediterranean belt: rare

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples