Physciaceae Rinodina bischoffii Growth type crustose. BLS conservation evaluation: LC NS Chemical results negative Widespread on calcareous (particularly limestone) rocks and pebbles Thin, scurfy, inconspicuous or pale grey thallus with prominent apothecia, the discs brownish to black, margins becoming excluded. Asci 8-spored, spores 1-septate, 14.5-20 x 10-12.5 µm with a strongly pigmented band round the centre and thin-walled apices. Micrograph below. Similar: Pyrenodesmia alociza (Caloplaca alociza) is also K- but epithecium K+ mauve-lilac. Caloplaca variabilis is K+ crimson.

Microscope photograph

Rinodina bischoffii
Ulwell Gap, Dorset. January 2016