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 slightly bullate areas of the host thallus, numerous, subglobose, 150-280 µm tall and 150-250 mm wide, the infection not producing necrotic patches wall: brown throughout centrum: I+ violet, K/I- hamathecium: interascal filaments abundant, branched, anastomosing, 1-2 µm thick asci: ±cylindrical, 60-80 x 15-17 µm, with mostly distichously arranged ascospores, 8-spored ascospores: dark brown, 1-septate, ellipsoid, with both cells ±equal in shape, usually not constricted at the septum, verruculose, frequently with a distinct gelatinous sheath, 13-16 x 7-8.5 µm. Hosts: thallus of Lecidea (mainly Lecidea fuscoatra); in the Sonoran area on L. tessellata World distribution: Europe, Canary Islands, and North America Sonoran distribution: Arizona. Notes: Polycoccum kerneri typically occurs on Lecidea fuscoatra, the infected parts of the host thallus becoming strongly bullate in some specimens. The material examined from the Sonoran region, however, occurred on Lecidea tessellata, and except for an unusual I+ violet reaction in the centrum and a less marked effect on the host thallus, the features observed are overall consistent with those of P. kerneri.