Dothideaceae Chevall. [as ‘Dothideae’], Fl. gén. env. Paris (Paris) 1: 446 (1826).
MycoBank number: MB 80715; Index Fungorum number: IF 80715; Facesoffungi number: FoF 00065, 151 species.
Biotrophic, saprobic or necrotrophic on twigs and other plant parts, rarely on leaves in terrestrial habitats. Sexual morph: Ascostromata immersed to erumpent or superficial, solitary to scattered, pulvinate or crustose, dark brown to black, globose to subglobose, uniloculate or multiloculate, without a distinct ostiole, apically opening by a lysigenous pore or by dehiscence, multi-layered ascostromata comprising pale to dark brown cells of textura angularis. Peridium of locules multi-layered, lightly pigmented to dark brown, thick-walled cells of textura angularis becoming flattened towards the inner layers. Hamathecium usually lacking pseudoparaphyses, and cellular pseudoparaphyses in some genera (e.g. Stylodothis and Uleodothis). Asci eight to multi- spored, bitunicate, fissitunicate, saccate to clavate, short-pedicellate, apically rounded with an ocular chamber. Ascospores 1–2-seriate, partially overlapping, muriform, small, hyaline to brown, transversely septate, constricted at the primary septum, sometimes wall smooth to verrucose, at times with a thin mucoid sheath. Asexual morph: Coelomycetous or hyphomycetous. Hyphae lightly pigmented to brown, verruculose, constricted at septa, giving rise to a hormonema-like synasexual morph. Conidiomata pycnidial, stromatic, immersed to erumpent, epidermal to subepidermal, solitary or aggregated, globose to subglobose to flask-shaped, sometimes irregular, dark brown to black, uniloculate to multi-loculate, sometimes convoluted with or without central ostioles. Conidiomata wall multi-layered, hyaline to brownish and dark brown cells of textura angularis. Conidiophores present, or reduced to conidiogenous cells, branched, septate, at the base hyaline to pale brown when present. Conidiogenous cells enteroblastic, phialidic, integrated to discrete, cylindrical or ampulliform to doliiform, determinate, hyaline to brown, smooth-walled, lining the inner cavity. Conidia cylindrical or subcylindrical to ovoid or oblong, hyaline, aseptate to one-septate, guttulate, smooth, granular or not (Thambugala et al. 2014a, Crous & Groenewald 2017).
Type – Dothidea Fr.
Notes – Generally, Dothideaceae is characterized by immersed to erumpent or superficial, uniloculate to multiloculate ascostromata lacking ostioles, 8- or poly-spored, bitunicate asci and hyaline or brown, transversely septate, or muriform, and often guttulate ascospores (Thambugala et al. 2014a, Hyde et al. 2018). We accept 13 genera in Dothideaceae: Delphinella, Dictyodothis, Dothidea, Dothiora, Endoconidioma, Endodothiora, Kabatina, Neocylindroseptoria, Phaeocryptopus, Plowrightia, Stylodothis, Sydowia and Uleodothis. Asteromellopsis, Cylindroseptoria, Hormonema, Neophaeocryptopus, Pringsheimia and Rhizosphaera were included in Dothideaceae by Wijayawardene et al. (2018). Asteromellopsis was introduced by Hess & Müller (1951) and the type species A. insculpta was described by considering the asexual morph observed in immature ascomata of Dothidea insculpta. However, we do not accept Asteromellopsis as a distinct genus in Dothideaceae because of its lack of supportive characters. Therefore, recollection, epitypification and multi-gene molecular analyses are needed for the type species of this genus to clarify its placement. Cylindroseptoria and Neophaeocryptopus which had been assigned to the family, were synonymized under Dothiora by Crous & Groenewald (2016) and Crous et al. (2018a), respectively. Neophaeocryptopus was established by Li et al. (2016a) as a distinct genus in Dothideaceae with the type species N. cytisi. Later, N. spartii was introduced by Hyde et al. (2017). We have confirmed that Neophaeocryptopus should be treated as a synonym of Dothiora, as it is grouped within Dothiora in the present phylogenetic analysis (Fig. 27), and there is also no morphological evidence to separate the genus from Dothiora. The asexual genus Hormonema has been considered the asexual morph of Sydowia polyspora (Thambugala et al. 2014a, Rossman et al. 2015, Humphries et al. 2017). Phylogenetic studies, including our analysis, show that a putative strain of the type species of Hormonema, H. dematioides and Sydowia polyspora clustered together (Bills et al. 2004, Thambugala et al. 2014a). Therefore, we do not accept Hormonema as a distinct genus in Dothideaceae. However, this genus requires recollection of the type to carry out further culture and molecular data assays to confirm the status of the genus. We exclude the genus Pringsheimia from Dothideaceae because the sequence data of the type and other species are not available in GenBank, and recollecting, molecular analysis, and epityping are needed to resolve the placement of this genus. However, we suggest keeping Pringsheimia in the genera incertae sedis, Dothideales. Further, Orton (1915) reported Rhizosphaera species as the asexual morph of Phaeocryptopus. Humphries et al. (2017) mentioned that Rhizosphaera pini strains are producing colonies with pycnidium-like structures, while a hormone-like morph is producing very large conidia. According to our multi-gene phylogenetic analysis, R. pini is separated as a distinct lineage with the Hormonema and Sydowia groups. Other Rhizosphaera species used in our phylogenetic analysis are grouped with Plowrightia species. However, Rhizosphaera abietis the type of Rhizosphaera, has no molecular data and needs to be recollected and sequenced in order to resolve the affinities of Rhizosphaera with Plowrightia in Dothideaceae. Therefore, we do not consider Rhizosphaera as a distinct genus in Dothideaceae.