ASCOMYCOTA | LECANOROMYCETES > LECANORALES > Lecanoraceae

Genus Lecidella, diminutive of Lecidea

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

Synonym:                      Lecidea elaeochroma

Habitat:                         Woodland, wayside trees, shrubs, fences

Substrata:                     Smooth barked trees

Growth form:                Corticolous and lignicolous

Thallus:                  Crustose

Apothecia:                    Lecideine

BLS identity rating:        Graded 2/5 (visual identification possible with care)

Thallus variable, rather smooth to slightly granular, usually shiny, minutely pleated or cracked dependent on the type of bark substratum; pale grey-white to yellowish-grey or yellowish-green in sunny, exposed site, becoming grey-green in shade or when moist; usually limited by a dark blue-black prothallus, although sometimes absent or broken, especially in isolated thallus; can form extensive mosaics, often with Lecanora chlarotera, on smooth-barked trees.

Apothecia can be abundant, usually scattered across the thallus, up to 1mm dia.; disc initially flat or slightly concave, blackish, with red tinges when young and moist, with a smooth thin black thalline margin, persistent at first, becoming twisted and finally excluded as the apothecia grows and becomes convex.

Forma elaeochroma as described; forma soralifera is similar, but with greenish-yellow soralia scattered over the surface; both forms can occur together.

Very common on smooth-barked trees, trunks and branches, where it's an early colonist; also, occurring on shrubs and fences.

Lecidella elaeochroma could be confused with Amandinea (Buellia) punctata, which is a rather similar-looking species that is also frequently found on trees. Whilst spot-testing would distinguish the species, Amandinea punctata typically has more apothecia that are spread, rather than scattered, across the thallus and, more importantly, are much smaller than those found in Lecidella elaeochroma, only growing to 0.5mm dia., which is a very noticeable difference if checked with a ruler.