ASCOMYCOTA | ARTHONIOMYCETES > ARTHONIALES > Arthoniaceae

Genus Arthonia, meaning 'to sprinkle' referring to the scattered apothecia

Common name:            Asterisk Lichen

Synonym:                     -

Habitat:                         Woodland, wayside trees

Substrata:                     Bark

Growth form:                Corticolous

Thallus:                 Crustose

Apothecia:                    Lirellate

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

Thallus rather thin, more or less immersed, typically forming small patches from 1-3cm across, smooth and invariably slightly cracked when viewed closely; whitish to pale grey, sometimes with a pale brown or olive tinge, and usually with a thin brown prothallus; lirellae variably shaped, from simple to rounded or substellate, or multi-branched stellate up to 2mm or so in diameter, flat or slightly convex, black, not pruinose.

Arthonia radiata is a reasonably distinctive, albeit variable, species with widespread distribution; typically found on smooth-barked trees and shrubs, often mosaic-forming.