ASCOMYCOTA | DOTHIDEOMYCETES > MONOBLASTIALES > Monoblastiaceae

Genus Acrocordia, meaning 'heart-shaped summit' referring to sectioned perithecium

Common name:            -

Synonyms:                     Arthopyrenia alba, Arthopyrenia gemmata

Habitat:                          Woodland, wayside trees

Substrata:                     Bark

Growth form:                Corticolous

Thallus:                 Crustose

Apothecia:                    Perithecial

BLS identity rating:        Graded 2/5 (visual identification possible, although microscopic examination recommended)

Thallus thin, immersed in the bark forming smooth patches, smooth, sometimes lightly cracked; whitish to pale grey or grey- green; perithecia small, black, hemispherical, from 0.5-1mm dia., slightly protruding to entirely immersed; the ostiole often eccentric and sometimes papilla-like; pycnidia dispersed, frequent, but rarely numerous.

Acrocordia gemmata is a widespread, but locally common species, which is absent from many areas due to historical air pollution; a quick look at the distribution map shows that the majority of confirmed records are from the south, west, north and Scotland; occurring mostly on rough bark of older trees, especially Ash (Fraxinus), Elm (Ulmus) and Oak (Quercus), more rarely on the smooth bark of Hazel (Corylus).

Could be confused with Anisomeridium biforme, although that species has smaller perithecia of 0.3-0.5mm dia., and more numerous pycnidia, and a thin black prothallus.

Although the example featured below is considered likely, it cannot be confirmed.