Anisomeridium robustum Orange, Coppins & Aptroot

   Thallus crustose relatively thin but well defined, smooth and rarely fissured or cracked, white, whitish, cream, sometimes with a black hypothallus in case of mosaic. Usually absence of perithecia but some authors have described them in the form of small blackish domes with a poorly developed ostiole. Conical pycnidia with a globose base terminating in a tapering tube-like appendage, 0.2-0.6 mm in diameter and 0.2-0.5 mm in height, black. Pycnidiospores extruded as a whitish paste at the top of the pycnidia, elliptical with a truncate base, 4.5-6.5 x 2.5-3 µm. Photobiont: Trentepohlia. No significant color chemical reactions. A rare taxon on the bark of deciduous trees in woodlands and humid oceanic forests.

N.B. Taxon recently differentiated from Anisomeridium polypori which differs by its less distinct thallus, thinner and above all more "crowded" by the presence of perithecia and pycnidia (slightly smaller), but there are intermediate taxa which are difficult to name...