Description: A crustose lichen of moderately rough tree bark in well-lit woodlands and open spaces, P. hemisphaerica forms sizeable patches of pale blue-grey thallus surrounded by a conspicuous broad white margin. Discs are absent. Search for it towards the base of mature trees where the large (1–2mm) C+ red, convex soralia should easily distinguish it. In Ireland, the species is thinly scattered throughout.

Key Identification Features:

• Muted blue-grey thallus with a broad white margin
• Discs unknown but thallus with hemispherical soralia that react C+ red.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Varicellaria hemisphaerica at iNaturalist World Species Observations database.