Squamarina cartilaginea (With.) P. James
Thallus squamulose, rosette-shaped, to 4-8 cm, consisting of large squamules, 0.5-1 mm thick, margin incised and rounded, pruinose, whitish, white-glaucous, pale grey-greenish when moist, pale brown-yellow to pale grey-yellowish when dry, lower surface darker, faint dark brown. Apothecia numerous, sessile, large, up to 2-3 mm diam., disc slightly convex, tinged-green, brown-redish, carnation-brown, exciple white, distinct but finally excluded. Elliptical spores, simple, 11-16 x 4-6 µm according to the literature, 12-16 x 4-7 according to our measurements. Photobiont: Chlorococcoïd. C-, K-, Pd- or P+ yellow (there are two chemotypes, but the specimen presented here are Pd+, and would be characteristic of the coastal morph). Rare species in our prospecting region because it comes from dry limestone dunes (tonsures) or dunes rich in shell debris and more rarely on limestone or basic rocks, see : Squamarina cartilaginea forme saxicole atlantique and Squamarina cartilaginea forme saxicole méditerranéenne.
N.B. This species is frequently parasited and notably its apothecia, then turning brown-black to black.