Life habit: lichenized Thallus: crustose, areolate, granulose, sometimes granulose-coralloid, rarely effigurate, gelatinous when wet surface: dark reddish brown or blackish, smooth or rimose, plane or uneven, sometimes granulose anatomy: ecorticate, homoiomerous, paraplectenchymatous or densely reticulate photobionts: primary one a chroococcoid cyanobacterium with reddish or purplish gelatinous sheath, secondary photobiont absent Ascomata: absent or present, apothecial, laminal or terminal on tiny, coralloid granules, orbicular, immersed to sessile, margin indistinct to prominent, with thin thalloid rim ontogeny: hemiangiocarpous, forming pycnoascocarps from ascogonia beneath pycnidia Ascoma anatomy: exciple hyaline, very thin or apparently lacking, hypothecium hyaline, epithecium brownish yellow asci: rostrate, Lecanoralean, with amyloid inner cap or prototunicate, nonamyloid but relatively thick walled ascospores: hyaline, simple, ellipsoid to broad ellipsoid; 5-18 x 3-10 Ám, 8-32 per ascus; wall: thin or becoming thick Conidiomata: absent or present, pycnidia laminal, immersed, ▒ pyriform, ostioles sometimes blackish; conidiophores: simple, cells elongated conidia: ellipsoid, c. 3 x 1 Ám, acrogenous Secondary metabolites: none detected Distribution: world-wide in arid to humid regions Substrate: predominantly on acidic rock. Notes: Species with long, filiform conidia and perithecioid apothecia with periphysoids around the "ostiole" are included in Cryptothele, a genus not reported from the study area so far. Pyrenopsis is usually identified by the presence of (Gloeocapsa-like) coccoid photobionts with reddish to purplish gelatinous sheaths. Further characteristics include the formation of ascogones and trichogynes beneath pycnidia (pycnoascocarps) and rather robust, apically often moniliform paraphyses. Usually, the asci are described as thick-walled with an apical dome or amyloid cap along the inner ascus wall. My own observations suggest that only a few species possess this type of unitunicate-rostrate asci. Most species have asci with rather thick walls, but lack any amyloid structures in the ascus apex. However, usually there is a strong deep blue staining of the outermost layer of the ascus wall in Lugol's solution. The genus is in urgent need of thorough revision and the present treatment is at best provisional. Probably more than one species is present in the Sonoran Desert region. All Pyrenopsis material distributed by Hasse (as P. phaeococca Tuck. and P. homoeopsis Nyl.) from southern California belongs elsewhere, mostly in Psorotichia. Currently Synalissa sect. Pyrenopsis Nyl. is considered a synonym of the Pyrenopsis.