Pertusariaceae Pertusaria pseudocorallina Growth type crustose Chemical results: K+ yellow > red (after 30 seconds), C-, P+ yellow, UV- Found on well-lit inland and coastal siliceous rocks. Smooth or warted, creamy-grey or yellowish-grey thallus. Short, round, brown-tipped isidia frequently erode leaving small craters in the thallus. The semi-globose apothecia rare, asci 2-spored, spores 150-200 x 50-80 µm. Similar: Pertusaria corallina

Pertusaria pseudocorallina
On chert, Portland, Dorset. February 2016