Julellafallaciosa (Stizenb. ex Arnold) R.C. Harris, in Egan, Bryologist 90(2): 163 (1987)

MycoBank number: MB 132219; Index Fungorum number: IF 132219; Facesoffungi number: FoF 08797.

Notes: The genus Julella has usually been considered a muriform-spored counterpart of Arthopyrenia sensu lato (Barr 1985, 1987b; Harris 1995). Species assigned to this genus are typically non-lichenized and possibly saprobic, about some doubtful lichenization has been discussed (Aptroot 2002a). The few studies available about this genus seem to disagree widely about species taxonomy. Thus, while Harris (1995) distinguished at least 13 species, Aptroot and van den Boom (1995) only accepted three. The latter authors included all forms with 2–4(-6) ascospores in a single species, J. lactea (A. Massal.) M.E. Barr, whereas Harris (1995) keyed out six species in this group, separated by ascospore size and numbers of ascospores per ascus. Among taxa with 8-spored asci, Aptroot and van den Boom (1995) distinguished two species: J. vitrispora (Cooke & Harkn.) M.E. Barr with longer ascospores and larger ascomata and J. sericea (A. Massal.) Coppins with shorter ascospores and smaller ascomata. In contrast, Harris (1995) accepted at least seven species in this group, distinguished by ascus shape and ascospore arrangement, size, and color, among other features. These differences are less the result of a disparate species concept (the theoretical approach of both treatments not being that much different) and more due to the fact that these authors studied a very different set of names and material and hence came to such different conclusions. Given the findings in other, similarly defined genera such as Arthopyr enia sensu lato, it is conceivable that Julella is also a highly heterogeneous assemblage not only including many species but also representing several, partly unrelated genera.