Lecidea phaeops Nyl.

    Thallus crustose strongly applied to its substrate, surface smooth to irregular, cracked, whitish, creamy white, greyish-white, glaucous white, sometimes with brownish, pinkish, greenish colored areas; hypothallus, if present, whitish but black in contact with other crustacean lichens. Apothecia very numerous and regularly dispersed throughout the thallus, resembling those of Aspicilia, immerrged in the thallus and irregular in shape, 0.2-0.6 mm, disc concave flat, blackish, margin inconspicuous. Spores narrowly elliptical, simple, 12-18 (23) x 5-7 µm according to the literature; (12) 14-18 (20) x (5) 7-8 µm according to our measurements. Pycnidia very frequent and very numerous in the form of large grayish-brown dots. Photobiont: green algae. C-, K + yellow, KC + yellow, P + yellow. Species typically found on the ever-humid sloping siliceous rocks of the ravines of oceanic forests, also on tree-lined coastal cliffs. Very easy to confuse with Herteliana gagei, whose habitat it often shares, but which is distinguished by its P- reaction, its more sessile and regular apothecia and its more bluish thallus.