Description: Thallus crustose, episubstratic, membranous with a granular surface, grey-white when dry, greenish when wet, becoming snow-white by crystals of calcium oxalates when drying in a herbarium, forming rounded, oval or irregular, 0.2-0.3 mm wide patches merging into 1-4 mm wide aggregates delimited by a pale prothallus. Surface with scattered, sterile setae that resemble those of the hyphophores; hyphophores laminal, their scales completely divided into a circle of 2-6, vertically oriented, 0.3-0.5 mm long, tapering cilia which are translucid to whitish, but often darkened at tips, and surround a greenish to rarely yellowish brown, distinctly prominent diahyphal mass formed of conidia-forming, moniliform hyphae strongly constricted at septa, and of spherical green algal cells. Apothecia and pycnidia unknown. Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: on leaves of evergreen shrubs and juvenile trees (e.g. Buxus, Abies) in the understory of very humid forests; widespread and apparently spreading in Europe from Brittany in Western France to the Western Caucasus, with a few records from the Western Alps (France). To be looked for in Italy.
Growth form: Crustose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by thallus fragmentation