Thallus effuse, immersed to thinly superficial. When superficial consisting of minute granules, 25-30 µm across or larger verrucose units, up to c. 100 µm acroos, dull olive-green to paler glaucous green. Photobiont Trentepohlia.
Anamorph: not observed.
Teleomorph: Ascomata apothecioid. Apothecia emerging from substratum/thallus as minute convex structures 75-100 µm across, when mature apothecia 125-250(-350) µm diam. Apothecia biatorine, sub-globose, pale to medium orange-brown, the disc usually paler than the margin and not becoming markedly concave, the margins not becoming excluded. True exciple pale within, orange-brown towards the edge. Hymenium colourless, c. 90 µm tall. Hypothecium poorly developed, colourless. Hamathecium of paraphyses, apparently simple (branching and anastomosing not observed) and containing inconspicuous, ± colourless oil droplets. Asci 8-spored, lacking a tholus, K/I-. Ascospores 1-septate, cells similar in size, (8.5-)10-12(-15) × 3-4 µm.
Not assessed. Its known habitat is threatened, which suggests that the species is too.
Has the habit of a small Gyalecta but other British Gyalecta species have more than one septum in their ascospores. It also looks somewhat like the other British species of Dimerella but the disc is not so concave and the colour a dull orange-brown.
Known in Britain from two English collections, in an ancient park in VC 23 (Oxfordshire) and in woodland within parkland in VC 11 (South Hampshire, New Forest).
On post-mature and veteran Quercus trunks, at dry edges of flushed tracks.