Pseudocercospora Speg., Anal. Mus. nac. B. Aires, Ser. 3 13: 437 (1910).
Index Fungorum number: IF 9559; Facesoffungi number: FoF 08551, 1498 morphological species (Species Fungorum 2021), > 100 species with molecular data.
Foliicolous, chiefly phytopathogenic, but also endophytic; commonly associated with leaf spots, but also occurring on fruits. Mycelium internal and external, consisting of smooth, septate, subhyaline to brown branched hyphae. Stroma absent to well-developed. Conidiophores in vivo arranged in loose to dense fascicles, sometimes forming distinct synnemata or sporodochia, emerging through stomata or erumpent through the cuticle, often arising from substomatal or subcuticular to intraepidermal stromata, or occurring singly on superficial hyphae, short to long, septate or continuous, i.e. conidiophores may be reduced to conidiogenous cells, simple to branched and straight to geniculate-sinuous, subhyaline, pale to dark olivaceous to brown, smooth to finely verruculose. Conidiogenous cells integrated, terminal, occasionally intercalary, polyblastic, sympodial, or monoblastic, proliferating percurrently via inconspicuous or darkened, irregular annellations, subhyaline, olivaceous, pale to dark brown, with inconspicous, or only thickened along the rim, or flat, and unthickened or almost so but refractive or even slightly darkened-refractive loci, but never pronounced. Conidia solitary, rarely in simple chains or disarticulating, subhyaline, olivaceous, pale to dark brown, usually scolecosporous, i.e. obclavatecylindrical, filiform, acicular, and transversely multi-euseptate, occasionally also with oblique to longitudinal septa, conidia rarely amero- to phragmosporous, short subcylindrical or ellipsoidal-ovoid, aseptate or only with few septa, apex subacute to obtuse, base obconically truncate to truncate, or bluntly rounded, with or without a minute marginal frill, straight to curved, rarely sigmoid, smooth to finely verruculose; hila usually unthickened, not darkened, at most somewhat refractive, occasionally slightly thickened along the rim, or rarely flat, unthickened or almost so, but slightly refractive or even slightly darkened-refractive, but never pronounced (Adapted from Videira et al. 2014).
Type species: Pseudocercospora vitis (Lév.) Speg.
Notes: Pseudocercospora was initially introduced by Spegazzini (1910) with P. vitis as type species. Pseudocercospora was established to accommodate synnematal analogues of Cercospora, as well as species that produce pigmented conidiogenous structures and conidia with neither thickened nor darkened conidial hila (Deighton 1976; Braun 1995). Deighton (1976) proposed that Pseudocercospora must be divided into several genera based on morphology and this was supported by several authors (Pons and Sutton 1988; Braun 1995; Crous and Braun 1996). Stewart et al. (1999) applied the first DNA phylogenetic analysis in the Mycosphaerella complex and reported that the latter is heterogeneous comprising over 100 species. Pseudocercospora resembles Cercoseptoria based on conidial shape, with conidia in the latter genus are acicular and those in the former are obclavate to cylindrical. von Arx (1983) reported Pseudocercospora together in a group of related genera characterized by hyaline or sub hyaline conidiogenous structures and unthickened, truncate, flat and broad conidiogenous loci. Later, Braun (1992) and Crous et al. (2000) reported that the arrangement of the conidiophores is not informative to differentiate between sections within Pseudocercospora because of transitions from solitary to fasciculate to subsynnematal conidiophores. Crous et al. (2001) observed a slight thickening of conidial scars as a taxonomically uninformative generic character. Phylogenetic analysis has reported that several genera are congeneric with Pseudocercospora and hence similar genera such as Cercostigmina, Paracercospora, Phaeoisariopsis and Pseudophaeoramularia were reduced to synonymy with Pseudocercospora (Stewart et al. 1999; Crous et al. 2001; Braun and Hill 2002; Crous et al. 2006). Braun and Crous (2006) suggested to conserve Pseudocercospora over Stigmina which signified an older generic name. Pseudocercospora is a distinct and well-supported genus in Mycosphaerellaceae.