Lecanora expallens

Lecanora expallens is a species of bark and sawn wood and locally has been recorded ona wide range of trees including Acer pseudoplatanus, Alnus glutinosa, Picea sitchensis, Prunus spinosa, Quercus sp. and Salix cinerea. The yellow-grey thallus is covered with pale yellow, farinose soredia and a pale grey prothallus shows on smooth bark. Apothecia are scarce, have pale discs with crenulate, sorediate margins. K+ yellow, C+ deep yellow or orange-red, P-, UV+ orange. One of several similar species including Pyrrhospora quernea (C+ orange & K-), L. barkmaniana (K+ yellow) and L. compallens (K- & C-).

Listed by Alan Orange in Flora of Glamorgan (Wade et al, 1994).