Porinaceae Porina borreri Growth type crustose. Photobiont Trentepohlia Chemical reactions negative. On rough bark of Oak, Ash and Sycamore, occasional on the smooth bark of old Holly and Beech. BLS conservation evaluation: LC NS Thallus grey-brown, green-brown or dark olive-black, small black perithecia <0.5mm, one third to half immersed. Involucrellum purplish-brown or brown. Spores 6-7(-8) septate, (23-)28-35(-40) x (3-)4.5-5(-5.5) µm. Micrographs below. Similar: Porina aenea. Smaller perithecia, spores 3-septate

Microscope photograph





Porina borreri
Holton Lee and Chettle, Dorset. December 2012 and 2018