Arthonia diploiciae Calat. & Diederich

in Calatayud & al., Mycotaxon, 55: 366, 1995.
Distribution: C - Tosc (Herb. von Brackel 372), Sar (Hafellner 1995b, Rizzi & al. 2011, Brackel 2016). S - Camp (Puntillo & Brackel 2016, Brackel 2016, 2021).
Description: Thallus inapparent, not lichenized, developing on the thalli of Diploicia canescens. Apothecia arthonioid, immarginate, numerous and aggregated into dark spots, sessile, 0.07-0.13 mm across, black, convex, with a rough surface. Proper exciple poorly developed; epithecium brown, 2-5 µm high; hymenium colourless to pale brown, 25-35 µm high, I+ red, K/I+ blue; paraphysoids branched and anastomosing, 2-3 µm thick, the apical cells 4-5 µm wide; hypothecium pale brown to brown, 20-35 µm high. Asci 4-spored, subglobose to broadly clavate, semi-fissitunicate, with a large apical dome and a distinct ocular chamber, with a minute K/I+ blue ring in the tholus, Arthonia-type. Ascospores 1-septate, hyaline, clavate or obovate, one of the 2 cells attenuated, smooth-walled, 8-13 x 3.5-5 µm. Photobiont absent. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: a recently-described lichenicolous fungus growing on Diploicia, to be looked for further, especially in Tyrrhenian Italy.
Growth form: Lichenicolous fungus
Substrata: rocks
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)
paras Diploicia canescens

Commonnes-rarity: (info)

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

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

Smithsonian Institution, National Museum of Natural History, Department of Botany; Owner: CC BY-SA 3.0

Smithsonian Institution, National Museum of Natural History, Department of Botany – Source:; Owner: CC BY-SA 3.0