Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.
Life habit: lichenicolous Ascomata: perithecial, dispersed, black, immersed in the thallus or the apothecia of the host, ostiolar region mostly flattened, with central pore, without papillae wall: brown, with the pigment deposited in the cell walls, composed of several layers of isodiametric to tangentially flattened cells, basally and towards the centrum paler and wall cells enlarged in the ostiolar region hymenium: hyaline hamathecium: in mature perithecia present as paraphysoids and shorter filaments of similar structure in the ostiolar region acting as periphyses paraphysoids: numerous, mostly with some ramifications and anastomoses, septate asci: bitunicate but not distinctly fissitunicate, ventricose to broadly cylindrical to slightly clavate, shortly stipitate, with apically enlarged ascal wall, without an ocular chamber, surrounded by amyloid hymenial gel, i.e. I+ blue, polyspored, c. 50 to more than 200 per ascus ascospores: brown, simple, with unsculptured walls Conidiomata: not observed Geography: widely distributed in the world, the individual species following in their distribution pattern that of their host genera Substrate: each species restricted to one host genus, the type species on Aspicilia, others on Haematomma, Brigantiaea, and Lecanora (L. frustulosa-group). Notes: Rosellinula was monographed by Hafellner (1985) under the generic name Roselliniella. However Santesson [in Eriksson and Hawksworth (1986)] has shown that for nomenclatural reasons Roselliniella cannot be used for this species group and therefore introduced the new generic name Rosellinula, that is now in common use. The systematic position of the genus is still unsettled. The positive I-reaction of the ascal gel indicates a certain relationship with some verrucarealean genera (Adelococcaceae), although euamyloid gel and a hamathecium in which the paraphysoids verge gradually into shorter elements with periphysal function are atypical for members of the order Verrrucariales. Thus, the systematic placement needs further studies. In the genus Rosellinula there is a negative correlation of spore size and spore number per ascus.