Bryologist 81: 599 (1978)
Protolog: Thallus corticola, fruticosus caespitosusque, 2-5 cm latus, pallide flavo-viridis, lobis linearibus, irregulariter ramosis, 0.5 - 2 mm latis vel basim versus latioribus, 3 - 5 mm latis, planis vel paulo canaiculatis aetate, superficie superiore nitida, longitudinaliter rugulosa, superficie inferiore simili, pseudocyphellata, pseudocyphellis sparsis vel moderate evolutis, rotundatis vel ellipticis, 0.2 - 0.5 mm longis, praecipue marginalibus. Apothecia numerosa, terminalia atque lateralia, disco modice pruinoso, 1 - 3 mm diametro; hymenium 45 - 55 µm; sporae 8ae, 1-septatae, rectae, 5-6 / 12 - 13 µm.
Type locality: USA, New Hampshire, Plymoth, on yellow birch, date lacking, C. E. Cummings, Cummings: Decadees of North American Lichens 43 (US - holotype).
Thallus: no soredia. Upper cortex (typical for the genus) composed of two layers, an outer thinner one that is paraplectenchymatous and in part decomposing and a thicker inner one of periclinally arranged, prosoplectenchymatous cells.
Distribution: Database
Note: Wetmore (1981: 490) or Willson & Vinyard (1986: 12) use the correct author names "H. Magn. ex Hale".
Taxonomy: A large series of morphologically similar specimens has varied and complex chemistries, including obtusatic acid, sekikaid acid, one of the "quintaria" unknowns, etc. (see Dey 1978: 81). Almost all of the chemical variants, incidentally, occur in southeastern United States from Arkansas to West Virginia and southward (Hale 1978: 601).
Chemistry: Usnic acid (Hale 1978: 599).
Ecology: Corticolous.