Description: Thallus inapparent, not lichenized, the hyphae developing inside the thalli of placodioid Variospora-species. Apothecia at first round, then lirelliform or ellipsoid, sessile, black, epruinose, (0.24-)0.3-0.5(-0.7) x (0.15-)0.2(0.3) mm, with a slit-like or slightly expanded disc, usually gathered into up to 1 mm wide, dense, suborbicular clusters. Proper exciple black, carbonized, (20-)30-70(-80) µm thick, formed of paraplectenchymatous cells, extending below the hymenium; epithecium covered in brown granules which are insoluble in K and in N, I+ blue; hymenium colourless, (80-)95-120(-130) µm high, I+ reddish, K/I+ blue; paraphysoids branched and anastomosing, 1.5-3 µm thick, the apical cells brown-pigmented, up to 5 µm wide; subhymenium colourless, 30-40 µm high, rarely inspersed with oil droplets; hypothecium brown-black, 20-30 µm high. Asci (6-)8-spored, narrowly clavate, fissitunicate, with a tholus and internal apical beak, Opegrapha-type. Ascospores 3-septate, hyaline (overmature spores may be brownish and warted), narrowly ellipsoid to slightly clavate, (14-)15-18(-19) x 5-7.5 µm, with a 0.5-1.5 µm thick, gelatinous perispore (not always observable). Photobiont absent. Spot tests: K-, C-, KC-, P-. Chemistry: without lichen substances.
Note: A recently-described lichenicolous fungus growing on Variospora flavescens, known from a few sites in the Mediterranean Region.
Italy, Sardinia, OG, Barbagia Seulo, between Seui and Ussussai, on the road to Monte Tonneri, limestone rock on the forest edge, 970 m 14.08.2014 A – infection on the thallus of Variospora flavescens in the zone between the vanished
inner parts (left down) and the healthy outer parts (right above); B: agglomeration of lirelloid and ellipsoid
ascomata on a gall-like structure. Scale bar A = 2 mm, B = 0.5 mm