Enchyllium tenax (Sw.) Gray var. tenax

    Thallus foliose, made of heaps of lobes, more or less rosette-shaped, 5-10 cm diam., lobes dark brown-olive, markedly swollen when moist, dark brown, wrinkled, membrane-like, thin when dry, occasionally presence of globular isidia. Apothecia often numerous, up to 2-3 mm diam., located near the rims or dispersed at the lobes' surface, disc flat, then convex, brown-black, brown-red, with a narrow full, smooth, concolourous and rarely granular margin. Ascospores broadly ellipsoid, 3-septate or submuriform, 15-25 x 6-10 µm. Pycnidia present. Photobiont: Nostoc. Rather common, not especially maritime, on rocks more or less calcareous or weakly acid, old walls, calcareous dunes, etc. notably of the aerohaline zone. N.B. On calcareous dunes compacted soils a less spreading and more hemispherical variety may be found, made of lobes more or less cylindrical and usually sterile:  Collema tenax var. ceranoides. Another  small and fertile variety with short and markedly swollen  lobes may be found on more or less mossy calcareous rocks: Collema tenax var. vulgare.*