Description: This is a crustose epiphyte of old tree bark and one that is linked with ancient woodland and canopy continuity. The thallus has a waxy grey surface but otherwise is rather nondescript. Of note are the spherical pale pink to chestnut-brown coloured discs (perithecia) which lay partly or wholly immersed in the bark but which, with wetting, swell to become visible. They are unusual in their seasonality and appear in greater number in the winter and early spring. Under the microscope the spore sacs or asci will be seen to be multispored and the spores three-septate with rounded ends. Mostly western Ireland; more local elsewhere.

Key Identification Features:

• Greyish waxy thallus with numerous small brown perithecia almost buried in the bark; wet the bark to see
• On rain tracks of beech and oak (more basic-barked specimens) with a cover of the liverwort Metzgeria furcata; the similar Porina leptalea has orange-red perithecia, eight-spored asci and blunter spores.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Thelopsis rubella at iNaturalist World Species Observations database.