Hyphal strands: absent Ascomata: superficial, black, initially closely appressed to the host thallus, later elevated and sometimes with a slightly constricted base, scattered or loosely aggregated, cushion-like, usually rounded, convex to flat, 70-120 µm in diam., 30-40 µm tall internal structure: wall of the external cells: dark brown, with a granular pigment, hyaline in the internal ones, cells 4-8 µm in diam. centrum: I- asci: subglobose or broadly ovate, 20-25 x 13-18 µm, 4-8-spored ascospores: initially hyaline but later brown, 1-septate, slightly constricted at the septum, obovate, halonate, 9-12 x 4-6 µm; wall: with a finely granular surface. Hosts: on Usnea in the Sonoran region, also known on thalli of foliose and fruticose lichens (e.g., Alectoria, Evernia, Letharia, Pseudevernia, Ramalina) World distribution: widespread, Northern and Southern Hemispheres Sonoran distribution: Arizona and southern California. Notes: Lichenostigma maureri belongs to subgenus Lichenostigma, with rounded ascomata not connected to dark superficial hyphal strands. A further species of the subgenus is L. rugosa, but in that taxon ascospore ornamentation is more coarse, and it occurs on Diploschistes species. Lichenostigma lecanorae has larger ascomata and ascospores, verrucose ascospores, and is restricted to Lecanora.