Johnalcornia aberrans (Alcorn) Y.P. Tan & R.G. Shivas, in Tan, Madrid, Crous & Shivas, Australas. Pl. Path.: 10.1007/s13313-014-0315-6 (2014).

Bipolaris aberrans Alcorn, Mycotaxon 39: 364 (1990)

Cochliobolus aberrans Alcorn, Mycotaxon 39: 362 (1990)

Parasitic on leaves. Sexual morph: Ascomata globose with a short neck. Asci cylindrical to fusoid, straight or curved. Ascospores hyaline, filiform, tightly coiled. Asexual morph: Conidiophores solitary or in fascicles, simple or branched, straight to flexuous, apically geniculate, cylindrical, smooth. Conidiogenous cells integrated, cylindrical, proliferating sympodially, smooth to verruculose, with thickened and conspicuous scars. Conidia solitary, straight to curved, smooth, hilum inconspicuous, distoseptate, germinating from both polar cells, first conidial septum median or submedian, second conidial septum delimiting the apical cell, third septum basal (Tan et al. 2014).

Notes: Johnalcornia was introduced by Tan et al. (2014) to accommodate Bipolaris aberrans and it is monotypic. Combined gene analysis of EF-1α, GAPDH, ITS and LSU has shown that J. aberrans forms a sister clade to the newly described genus Porocercospora. Johnalcornia differs from Porocercospora in having distinctive conidia-like chlamydospores as well as comparatively thick-walled, geniculate conidiophores, with conidiogenous cells that have conspicuous scars. Johnalcornia further differs from related genera by forming the second conidial septum in the apical cell. In our phylogenetic analysis we also obtain the similar results where the type strain of J. aberrans forms a distinct clade sister to Porocercospora thus we accept Johnalcornia as a separate genus in the family Pleosporaceae.

Fig. 1 Johnalcornia aberrans (Redrawn from the holotype in Tan et al. (2014), Fig 2). Scale bars: 10 μm