Order: Lecanorales Family: Bacidiaceae
Species: Japewiella tavaresiana
Photos: On Willow. Gougane Barra, Cork, SW Ireland.
Identified by John Douglass
Immersed or thin white thallus, usually with a thin, dark prothallus. Reddish-brown discs darkening to dark brown or black. The ascus is 8-spored with simple spores 13-18 x 8-10 Ám. Micro photo below.
On bark and twigs of smooth barked trees, most frequent on Salix in damp woods and willow carr. Often with Lecanora jamesii.
Chemical reactions usually negative, very rarely K+ pale yellow.