ASCOMYCOTA | LECANOROMYCETES > TELOSCHISTALES > Teloschistacae

Genus Caloplaca, meaning 'beautiful patches'

Common name:             Grey-rimmed Firedot Lichen

Synonym:                    -

Habitat:                          Varied, but montane for this entry

Substrata:                      Bark, weathered wood

Growth form:                Corticolous, lignicolous        

Thallus:                 Crustose

Apothecia:                    Lecanorine

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

Thallus very thin, sometimes inconspicuous but, where visible, smooth and light grey in colour; apothecia lecanorine, tiny, up to 2mm diameter, generally quite numerous and typically scattered rather than in clusters, sessile with flat, bright-coloured, roughened discs that range from yellow to brownish-orange, although looking more yellow-lemon or yellow-green when wet; the discs have reasonably thick, somewhat swollen-looking and raised, distinctive grey thalline margins.

Caloplaca cerina is normally found on basic-barked shrubs or deciduous trees, notably Acer and Populus species, but also occasionally on weathered wood as was the case with the example featured here, which was photographed on a rough and well-worn timber handrail in Austria that was alongside some steps at the edge of an alpine meadow.

As a point of interest, it has been suggested that the large bright orange growths are a species of jellyspot fungus, but I'm rather doubtful as the structures look very disc-shaped to me. Unfortunately, I wasn't focusing on them, but they could possibly be Athalia (Caloplaca) holocarpa. Additionally, there are at least two, more likely three, other lichen species in this photo that haven't been identified.