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). 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.*