Alyxoria varia (Pers.) Ertz & Tehler
=Opegrapha varia Pers.
Opegrapha lichenoides Pers.
Thallus crustose, very thin and inconspicious, more or less smooth, dirty white, pale gray, pale gray-brownish, sometimes a little brownish. Apothecia lirelliform, rather short: 1-3 x 0.2-0.5 mm, not very high: 0.08-0.12 mm in height, stout, simple and very rarely branched or star-shaped, blackish, sometimes powdered with greenish, disc at the bottom of a very variable slit, more or less open (but often more open in the center), blackish, greyish (this variability has generated the description of many species and varieties which are today discussed and not always recognized), wide rim, black. Utriform asci containing 8 spores very tightly packed together, which in optical section may suggest that they contain only 4 or 6 spores. Spores with a thin perispore, fusiform and a little keyed, 4-6 times septate, with somewhat rounded ends and sometimes a larger cell in the center, colorless in youth then reddish-brown when mature, 20-37 x 6- 9 µm according to the literature, 22-32 x 5-8 according to our measurements. Grayish pycnidia, bacilliform pycnoconidia, colorless, 3-5 x 1 µm. No characteristic colored chemical reactions. Fairly variable species of which many taxa have been described, occurring on the basic bark of deciduous trees.