Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Perithecia: immersed in the host thallus, subglobose, 100200 µm wide, scattered or slightly aggregated, not producing neither distinct galls, nor deformations or necrotic patches in the host thallus wall: dark brown in the upper part of ascomata, paler in the lower part centrum: I-, K/I- hamathecium: interascal filaments abundant, branched, anastomosing, 1-2 µm thick asci: ±: clavate, 65-90 x 14-22 µm, with distichously arranged ascospores, (6-)8-spored ascospores: dark brown, 1-septate, ellipsoid, with both cells ±equal in shape, or lower cell sometimes slightly narrower, usually not constricted at the septum, coarsely verruculose, commonly with a distinct gelatinous sheath, 17-25 x 6-11 µm. Host: thallus of Dimelaena oreina World distribution: Spain and Mexico Sonoran distribution: Chihuahua. Notes: The relatively large, coarsely ornamented ascospores with a distinct gelatinous sheath c. 2 µm wide are distinctive of this species. Dimelaena oreina hosts a further species with perithecioid ascomata, 8-spored asci and brown ascospores: Endococcus oreinae Hafellner. Its ascospores are brown to pale brown, smaller, 16-20 x 5-7 µm, not ornamented and without a gelatinous sheath, and, like all species of Endococcus, the ascomata show persistent periphysoids and lack interascal filaments.