Thallus crustose, continuous, thin to finely granular, pale green to fawn; granules (15-)20-35(-50) µm diam.; photobiont alga, cells 5-10(-12) µm diam. Ascomata biatorine apothecia, minute (0.2-)0.3-0.6(-0.7) mm diam., flat, white, beige or orange-pink; exciple hyaline, with cellular lumina (to 7 µm wide) towards outer edge and in lower part; hymenium hyaline, 35-50(-55) µm high; paraphyses 1.5-2 µm wide, simple, or a few forked above, apices often swollen, to 5 µm; hypothecium hyaline. Asci clavate to cylindrical-clavate, 8-spored; ascospores hyaline, acicular, 3- to 7-septate, (21-)24-48 × 1-1.5(-2) µm. Pycnidia ± immersed, white; conidia 21-40 × 1 µm, curved.
Chemistry. Not reported.
Substrate and Habitat. On semishaded to shaded calcareous rock and bark.
Distribution. Eurasia, North America, South America (Galapagos Islands); in North Carolina scattered throughout.
Coppins, B.J. & A. Aptroot. (2009) Bacidia De Not. (1846). Pp. 189-207 in Smith, C.W., A. Aptroot, B.J. Coppins, A. Fletcher, O.L. Gilbert, P.W. James & P.A. Wolseley (eds.). 2009. The Lichens of Great Britain and Ireland. The British Lichen Society, London (description as Bacidia delicata).
Leighton, W.A. (1879) The lichen-flora of Great Britain, Ireland, and the Channel Islands, 3rd ed. Shrewsbury [England]. 547 pp (original description as Lecidea effusa var. delicata).