Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Vegetative hyphae: brown to dark brown, torulose, branched and anastomosed, (5-)6-9(-10) µm in diam., forming a reticulum inside the epinecral layer of the host thallus, verruculose, BCr- Pseudothecia: blackish brown, immersed, globose, (40-)50-70(-80) µm in diam. wall: brown, upper and lower part brown, composed by 1-2 cell layers, mostly 5-10 µm thick; hyphae: 4.5-9.5 µm wide and 4.5-8 µm long hamathecium: lacking paraphysoids periphyses: sometimes very short or absent asci: bitunicate, sessile, oval to broadly ellipsoid or almost globose, 22-28(-33) x 15-19 µm, 8-spored; epiplasma: in young asci I+ orange (dextrinoid reaction), with broad ocular chamber ascospores: medium to dark brownish when mature, 1-septate, with lower cell a little longer then the upper one, clearly constricted at the septa, ellipsoid, often with oil droplets, (10-)11.5-14(-16) x (4.5-)5-6.5(-8) µm, with rounded apices, 1-2-seriate inside of the ascus; epispore: smooth, thin-walled, only seldom forming a thin halo, BCr- Pycnidia: not observed. Hosts: in the epinecral layer of the thallus of Protoparmelia badia, Rhizoplaca melanophthalma, Sporastatia testudinea and Tephromela armeniaca World distribution: Europe and North America (U.S.A.) Sonoran distribution: Arizona. Notes: Sphaerellothecium contextum and S. abditum have characteristic dark brown vegetative hyphal cells, that develop thicker walls at the light-exposed upper side than at the lower side.