Acarosporaceae Myriospora rufescens (Acarospora rufescens) Growth type crustose Chemical results negative Local distribution on siliceous substrata including sandstone, monuments, gravestones, and walls. Thallus smooth, forming pale brown, areolate crust, aureoles angular with concave surface. Each areole contains one or two immersed apothecia, margins slightly raised. Asci multi-spored, spores 3-4 × 1-1.5 µm. Microscope photograph below. Similar: M. smaragdula usually K+ red, 3-7 apothecia in each areole

Microscope photograph

Myriospora rufescens
On heathstone. Redhorn Bay, Dorset. June 2015