Bacidia laurocerasi (Delise ex Duby) Zahlbr.

    Thallus crustose, thin, smooth to minutely cracked, grey-whitish, pale grey-greenish, sometimes grey-greenish tinged blue when fresh. Apothecia usually numerous, scattered all over the thallus, 0.3-1 mm diam., sessile, plane with a concolourous margin, or slightly brown-purple (K+ dark brown purple under microscope) or slightly convex, margin inconspicuous, dark brown, brown-black when shaded, blackish in well-lit areas (N.B. Apothecia of different shapes and different colors may be present on the same thallus). Epithecium purple in KOH and nitric acid. Ascii 8-spored, 50-70 x 15-20 µm  according to our measures. Ascospores colourless, acicular, straight or slightly curved, or wavy (notably inside ascus), 7-15-septate, 35-80 x 2,5-4 µm according to the literature, 30-60 x 2.5-4 µm according to our measures. Photobiont: chlorococcoid. Chemical spot tests negative. Rare or understated, on weakly acid or alkaline barks of trunks, branches or twigs of trees in shaded oceanic woodlands and also in dense garden hedges.

_ In the field, not to be confused with Lecidella elaeochroma of which the thallus is more yellow-greenish and usually C+ orange.

_ See also  Bacidia biatorina of which the thallus is rougher and darker, ascospores larger, and the Northern species  Baciidia caesiovirens.