Phaeosphaeria I. Miyake, Bot. Mag., Tokyo 23: 93 (1909).
Index Fungorum number: IF 3951; Facesoffungi number: FoF 00233, 210 morphological species (171 species as Phaeosphaeria, 39 species as Phaeoseptoria; Species Fungorum, 2022), 19 species with molecular data.
Saprobic or parasitic on host. Sexual morph: Ascomata scattered or sometimes clustered, or solitary, immersed to semi-immersed, globose to subglobose, brown to dark brown, with pore-like or papillate central ostiole. Peridium thin, smooth-walled, of equal thickness, comprising 2–3 layers of brown to dark brown, pseudoparenchymatous cells of textura angularis. Hamathecium comprising filiform, sparse, broadly cellular pseudoparaphyses, branching at the apex, often constricted at the septa. Asci 8-spored, bitunicate, fissitunicate, cylindrical to cylindric-clavate, short pedicellate or subsessile, apically rounded with an ocular chamber. Ascospores overlapping biseriate, ellipsoidal, cylindrical or fusiform, pale brown to brown, phragmosporous, with rounded ends, constricted at the septum smooth-walled. Asexual morph: reported as Phaeoseptoria and Stagonospora (Adapted from Verkley et al., 2004; Kirk et al., 2008 and Hyde et al., 2013).
Type species: Phaeosphaeria oryzae I. Miyake
Notes: Phaeosphaeria was introduced by Miyake (1909) with P. oryzae as type species. Phaeosphaeria is characterized by scattered or clustered ascomata, fissitunicate, cylindrical to cylindric-clavate asci and ellipsoidal, or fusiform, pale brown to brown, phragmosporous ascospores. The asexual morph of Phaeosphaeria is reported as Phaeoseptoria and Stagonospora. Holm (1957) reported the presence of pseudoparaphyses in P. oryzae, reestablished Phaeosphaeria, and accommodated some Leptosphaeria (s. l.) taxa characterized by somewhat small ascomata occurring on monocotyledons. Eriksson (1967) designated a lectotype of Phaeosphaeria but the genus was considered as a synonym of Leptosphaeria for a long time. Several members of Phaeosphaeria have a gelatinous sheaths surrounding the ascospores while some are dictyosporous (Eriksson, 1967). Shoemaker and Babcock (1989) accepted 114 species of Phaeosphaeria while Kirk et al. (2008) accepted 80 species under Phaeosphaeria with several taxa having Stagonospora anamorphs. Phaeosphaeria previously consisted of six genera based on ascospores shape and septation such as Fusispora, Ovispora, Phaeosphaeria, Sicispora, Spathispora and Vagispora (Shoemaker & Babcock, 1989; Zhang et al., 2012; Phookamsak et al., 2014). Various authors reported that Phaeosphaeria and Leptosphaeria are two distinct genera accommodated in separate families but the concept of subgenera was not supported by phylogenetic evidence (Câmara et al., 2002; Schoch et al., 2009b; Zhang et al., 2009). Câmara et al. (2002) mentioned that the asexual morph of Phaeosphaeria is characterized by elongate to filiform, hyaline or pale brown, multi-septate conidia produced from holoblastic conidiogenous cells in pycnidial conidiomata. In the phylogenetic analysis of Zhang et al. (2009), Phaeosphaeria formed four distinct clades with Phaeosphaeria oryzae, P. juncina, P. musae and a Phaeoseptoria sp. commonly found on monocotyledons. Phaeosphaeria is a polyphyletic genus and several taxa in Phaeosphaeria sensu lato clustered in different genera in Phaeosphaeriaceae namely Amarenomyces, Juncaceicola, Loratospora, Neosetophoma, Parastagonospora, Phaeopoacea, Pseudophaeosphaeria, Septoriella and in other families in Pleosporales (Quaedvlieg et al., 2013; Ariyawansa et al., 2014d, 2015a; Tanaka et al., 2015a; Hyde et al., 2016, 2017, 2020b; Tennakoon et al., 2016; Thambugala et al., 2017b; Marin-Felix et al., 2019). Quaedvlieg et al. (2013) designated an epitype of Phaeosphaeria oryzae and synonymized Phaeoseptoria papayae as the asexual morph of Phaeosphaeria, is characterized by septoria-like coelomycetous, forming hyaline to brown, cylindrical to subcylindrical conidia (Quaedvlieg et al., 2013; Phookamsak et al., 2014c; Hyde et al., 2017; Phookamsak et al., 2014). Phaeosphaeria is a distinct and type genus of Phaeosphaeriaceae. Molecular markers available for Phaeosphaeria include LSU, SSU, ITS and TEF1.