Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Mycelium: I- Apothecia: first immersed, soon superficial, sessile, 300-400 µm in diam., 150-250 ? tall disc: black, covered with a greenish pruina when young, from the beginning strongly convex epihymenium: dark brown hymenium: hyaline to brownish, c. 75 µm hypothecium: brown, K-, 100-150 µm thick asci: elongate ellipsoid to clavate, 8-spored, 40-45 x 12-15 µm ascospores: brown, slightly verrucose, at first 1-, then 3-septate, not dividing in part-cells, usually constricted at the middle septum, upper half broader than the lower half, 14-17(-20) x 5-7 µm Pycnidia: black, half immersed, 55-75 µm in diam., with a brown wall; conidiogenous cells: ampulliform to lageniform, 6-10 x 3-5 µm conidia: hyaline, obpyriform, surface ±smooth, 3-5(-6) x 2-3.5(-4) µm . Hosts: apothecial disc, rarely thallus of Ramalina species World distribution: Europe and the U.S.A. Sonoran distribution: once collected in California. Note: Abrothallus suecicus is easily recognized by the 3-septate ascospores, and by its host-selection (apothecia of Ramalina).