Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2002. Lichen Flora of the Greater Sonoran Desert Region. Vol 1.
Life habit: non-lichenized, saprophytic, or possibly facultatively lichenized Thallus: superficially absent but within the substrate photobiont: absent or possibly facultatively Trentepohlia, secondary photobiont absent Ascomata: perithecial, circular to ellipsoid in outline involucrellum: present, dark, usually laterally spreading, composed of compacted hyphae and bark cells ascomatal wall: greenish or brown, K+ greenish, N-, black, not continuous below the hamathecium hamathecium: richly branched pseudoparaphyses, anastomosing above the asci, non-amyloid asci: bitunicate, clavate, with tholus, non-amyloid, inner wall thickened towards the apex, ± with a shallow, broad ocular chamber ascospores: hyaline, ellipsoid to clavate, muriform with eusepta, 7-22 x 13-65 micrometer; walls: not ornamented Conidiomata: pycnidial, black conidia: bacilliform, simple, colorless Secondary metabolites: none detected Geography: mostly subtropical Substrate: on bark. Notes: For the species concept in the genus Julella the publication of Aptroot and van den Boom (1995) is followed. The much narrower species concept proposed by Harris (1995) was tested with the specimens from the Sonoran Desert and found not to be adequate. In the latter species concept much emphasis is laid on the ascus shape and the ascospore arrangement, two very variable characters, even within a single ascoma. The genus is characterized by branched pseudoparaphyses, which are anastomosing above the asci and muriform ascospores. All accepted species are either non-lichenized bark saprophytes or possibly facultatively lichenized.