Collema glebulentum  

Thallus 3-6 cm diam., foliose, membrane-like, rounded or irregular, closely appressed, ± deeply lobate. Lobes 5(-10) mm wide, 0.1-0.25 mm thick, often numerous, rounded or extended, ± overlapping or with contiguous, ascending margins. Upper surface dark olive-green to black, folded and conspicuously wavy, margin entire or at times crenate or isidiate, never swollen. Isidia ca 0.1 mm diam., to 1.5 mm long, terete, branched, globose when young, rarely becoming flattened, usually numerous, often forming a dense, coarsely areolate crust on
older parts of thallus.
Anamorph: not known.
Teleomorph: not known.