ASCOMYCOTA | LECANOROMYCETES > TELOSCHISTALES > Teloschistacae

Genus Caloplaca, meaning 'beautiful patches'

Common name:            -

Synonym:                      Blastenia creularia

Habitat:                          Coastal and urban

Substrata:                      Rock

Growth form:                Saxicolous    

Thallus:                 Crustose

Apothecia:                    Lecideine

BLS identity rating:        Graded 1/5 (identification should be relatively straightforward)

Thallus rough, rather thick, cracked to areolate, spreading to 10cm maximum, pale to dark grey; apothecia can be numerous, normally rounded, but occasionally distorted; discs are rough, initially flat, but become convex, sometimes almost bulging, typically rust-red in colour, but can be much darker; the margins are a shade or so lighter; some specimens will have tiny dark spots.

In dry weather, Caloplaca crenularia is hardly distinguishable from Caloplaca ceracea, but when wet this species retains its colour, whereas Caloplaca ceracea becomes distinctly greener. If spot tested, the apothecia are K + crimson.

The species can be found on both coastal and inland siliceous rocks, either well-lit or in shade. It is reasonably common and widespread, although more frequently occurring in the west and north.