Annals Sci. Nat., Bot., Sér. 3, 10: 134 (1848).

Basionym: Collema phyllocarpum Pers., in Gaudichaud-Beaupré in Freycinet, Voy. Uranie., Bot.: 204 (1827) [1826-1830].

Thallus: foliose, gray to dark black when dry, blackish when wet, foliose, adnate, thick, swelling considerably when wet; outline irregular; lobes distinct, narrow and elongated, frequently anastomosing; surface rugose, irregularly contorted and folded, plicate; lacking isidia, but sometimes lobulate along the thallus lobes and apothecial margin. Apothecia common, distinctly stalked, submarginal, expanded; disk pale to deep reddish brown, initially concave but soon flattened; margin lecanorine, strongly folded, lammellate, occasionally lobulate, concolorous with the thallus, with a broad paraplectenchymatous out thalline exciple and an inner, indistinct, thin, prosoplectenchymatous proper exciple; ascospores ellipsoid, muriform, 3-5 transversely septate, 1 longitudinally septate, 22-33 / 10-14 µm (Bungartz 2008: 151).

Ecology: On bark or wood, rarely on rock, typically in dry habitats (Bungartz 2008: 151).