Nephroma parile (Ach.) Ach.
Thallus foliose, forming irregular rosettes, to 5-10 cm across, lobes 3-8 mm wide, rather thick and tough, margin more or less ascending, upper surface smooth, brown-greyish, brown-olivaceous when moist, covered with grey to bluish pustulous soralia towards the margins, potentially spreading to the whole lobes, medulla whitish, lower surface without rhizines, smooth or minutely tomentose, pale brown, darker towards the center. Very seldom fertile. Apothecia immature emerging on lower surface margins, discs brownish. Ascospores brownish, narrowly ellipsoid, 3-septate, 18-20 x 6-7 µm. Photobiont: Nostoc. Medulla: K- or rarely K+ more or less yellow. Rare, on mossy trunks and rocks of old humid oceanic woodlands. N.B. The following 2 species appears rather similar on the field: Peltigera collina with rhizines and veins on lower surface and Sticta limbata with whitish cyphella on the markedly tomentose lower surface.*