Naetrocymbaceae Naetrocymbe saxicola (Arthopyrenia saxicola) Growth type crustose Chemical results negative. Infrequent, with a scattered distribution on exposed or sometimes shaded, hard limestone. BLS conservation evaluation: LC NS The immersed or superficial, greyish-brown thallus is sometimes slightly mottled and is often discoloured by cyanobacteria. Small black perithecia are half to completely immersed, the spores hyaline, 1-septate, 19-20.5(-22) x 5-6.5 µm. Pycnidia frequent. Photobiont Trentepohlia. Similar: Porina linearis has 3-septate spores .

Arthopyrenia saxicola
On limestone, Portland, Dorset. February 2016