A new freshwater Porina (Porinaceae, Ostropales) from Great Britain. (2nd November 2015) - Orange, Alan
Abstract: Porina rivalis Orange is described as new from rocks in streams in Great Britain. The involucrellum is yellow or orange within, but dark grey to purplish red at the surface; the ascospores are 3-septate, 13·0–18·5×4·0–5·5 μm.