ASCOMYCOTA | LECANOROMYCETES > LECANORALES > Lecanoracea

Genus Lecanora, meaning 'beautiful small bowl' - from the shape of the apothecia

Common name:            Members of the genus collectively known as 'rim lichens'

Synonym:                    -

Primary habitat:            Various

Usual substrata:            Rock, occasionally worked timber

Growth form:                Saxicolous, lignicolous

Thallus:                  Crustose

Apothecia:                    Lecanorine

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

Thallus immersed and inconspicuous, smooth and flat, most often composed of scattered areoles or granules, rarely continuous; usually grey-yellowish to yellowish-green, occasionally greyish-brown; indistinct or more obvious black prothallus; apothecia often numerous, scattered or tightly grouped, which has the effect of slightly deforming them, slightly sessile and constricted at the base, typically 0.3-1.0mm dia.; disc pale yellowish to greenish-yellow or jade, smooth, flat then later convex, thalline margin initially well-developed and distinct, but becoming crenulate or excluded.

Lecanora polytropa is a common and widespread species that can be found on siliceous rocks and walls, but also on worked timber especially in upland areas. Given that there are no specific records of it occurring on deadwood makes the identity of the specimen featured below rather questionable, but it was spot-tested with a KC+ yellow reaction, albeit not that conclusively. The more obvious candidate was the rather similar looking Lecanora symmicta, but there was no C+ orange reaction, which tended to make Lecanora polytropa the more likely species.