Description: P. chlorospila and its relative P. macrospora are smooth-bark-encrusting lichens that can be recognised in an instant. The characters are such as to be completely unlike other Irish species. Both combine a greenish, wax-like thallus with the presence of minute, white flecks trapped within the waxy layer like a still photograph of falling snow. Both form tight bark mosaics with a black dividing border. Spherical black discs (perithecia) are also present and it is attention to the size of these that will help determine the species. In P. chlorospila the discs are less than 0.4mm in diameter. Often the two will grow together on smooth-barked trees (for example, holly, beech and hazel) in shaded woodland or in groves.

Key Identification Features:

• Crustose epiphyte with pale brown to olive green wax-like thallus scattered with small, white spots or flecks
• Discs black, small, rarely exceeding 0.3mm.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Pyrenula chlorospila at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Pyrenula chlorospila at iNaturalist World Species Observations database.