Abrothallus parmotrematis P. Diederich

Lichenicolous fungus occurring on lichens of the genus Parmotrema.

        The mycelium of this fungus develops in the thallus of the host, the infection being revealed only by the appearance of apothecia. Usually in its fertile form (teleomorph) with apothecia 0.1 to 0.5 mm in diameter, first as posed on the thallus then slightly raised, strongly convex and subglobular then at the end less convex and flatter, black, surface finely granular sometimes (but rarely) with a greenish-yellow pruina. Asci in club with fragile walls, with 8 spores. Claviform spores with rounded ends, olive-brown if immature then brownish, 1-septate delimiting 2 asymmetric cells, one of which is larger, finely warty in network, (12) 13-16.5 (20) x 5-6.5 µm according to the literature; 13-15 (18) x 5-7 µm according to our measurements. Paraphyses septate more or less agglutinated. Pycnidia sometimes present, black with a reddish-brown top. Species occuring on lichens of the genus Parmotrema, (here on Parmotrema perlatum and Parmotrema reticulatum on the same tree trunk (Quercus), very close (if not conspecific!) of Abrothallus parmeliarum which comes on lichens of the genus Parmelia ss. str.

P. DIEDERICH _ Description of Abrothallus parmotrematis sp. nov. (Lichenicolous Ascomycota). 2011. Bulletin of the Société des naturalistes luxembourgeois. 112: 25-34.