Vouauxiella lichenicola (Linds.) Petr. & Syd.
Lichenicolous fungus parasitic on Lecanora sp.
Only known anamorph:
Characterized by its pycnidia, 80-120 µm in diameter, black, subglobose, opening through an irregular orifice, immersed in the hymenium of the host's apothecia (more rarely on the thalline edge or the thallus). These pycnidia contain bundles of conidia arranged in a chain which split to give elliptical pycnidioconidia with truncated ends (slightly rectangular appearance), grayish, with 2 guttules, smooth to slightly warty, 6-9 x 3-4 µm depending on the literature, 5-7 x 2.5-3.5 according to our measurements. Quite common species (but going unnoticed) occurring on the discs of the apothecia of Lecanora sp. corticolous or lignicolous in particular from the group of Lecanora chlarotera.
N.B. There are much rarer related species which require microscopic examination to be separated, in particular Vouauxiella verrucosa (Vouaux) Petr. & Syd. which has warty pycnidioconidia, parasite (specific?) of the disc of the apothecia of Lecanora chlarotera
N.B. The microscopic appearance of this parasite and its chains of pycnidioconidia are reminiscent of proglottids of Taenia saginata...