Blennothalia crispa (Huds.) Otalora, P.M. Jorg. & Wedin
Collema crispum (Huds.) Weber ex F. H. Wigg.
Thallus foliose up to 5 cm diam., made of numerous lobes forming more or less rosettes, frequently overlapping, curly-like, rounded at apices, margins flexuose, 1-5 mm wide, thin, wrinkled, dark-brown to olive-brown when dry, thicker but not swollen and olive-brown to olive-brown, grey-green tinged blue when moist, upper surface with a few subglobose to slightly squamulose isidia, mostly at the lobes centers, often together with numerous small secondary lobes, lower surface often with white rhizines. Apothecia rare, 1-2 mm diam., disc flat, dark brown-red, thalline exciple often bearing lobules. Ascospores subellipsoid or ± oval, 3-6-septate, 26-34 x 13-15 µm. Photobiont: Nostoc. Chemical spot tests negative. Not especially maritime, on calcareous substratum, sometimes on mortar of old walls in sheltered conditions near the coasts.