Caloplaca sol(Teloschistaceae), a new coastal lichen from Great Britain

Caloplaca solis described as a new species from limestone and basic siliceous rocks on the southern and western coasts of Great Britain. It is characterized by a well-developed, crustose, non-placodioid, epilithic, cracked, orange-yellow thallus, almost concolorous apothecia up to 0·66 mm diameter, and ascosporesc. 11·0–12·2–13·0 µm long with a septumc. 0·4×the ascospore length.Caloplaca dalmaticais related but differs in the endolithic or only thinly epilithic thallus.Caloplaca marinais darker orange in colour, with more convex areoles, and is mostly confined to the splash zone of the seashore.Caloplaca maritimadiffers in the typically more convex, sometimes isolated areoles, and often in the presence of a crenulate thalline margin in young apothecia.Caloplaca itianais newly reported from Great Britain from coastal limestone; it differs fromC. solin the thallus being endolithic or almost so, and fromC. dalmaticain the more completely endolithic thallus and the larger ascospores.