Mycosphaerellaceae Lindau, in Engler & Prantl, Nat. Pflanzenfam., Teil. I (Leipzig) 1(1): 421 (1897).
MycoBank number: MB 81043; Index Fungorum number: IF 81043; Facesoffungi number: FoF 00119, >5900 species.
≡ Sphaerellaceae Nitschke, Verh. Naturhist. Vereins Preuss. Rheinl. 26: 74. 1869, nom. illeg. (Art. 18.3 and 57.1), non Sphaerellaceae (algae).
Pathogens, endophytes, saprobes, epiphytes on flowering plants or lichens as well as fungicolous on other fungi. Sexual morph: Ascostromata solitary to gregarious, semi-immersed to superficial, dark brown to black, circular to elongate, stromatic, uni- to multi-loculate, sometimes forming pseudostroma or clypeus, or forming hypostroma within ovary of host, glabrous to setose, ostiolate. Ascomata dark brown to black, immersed to semi-immersed in raised, superficial pseudostroma or hypostroma, scattered to clustered, globose to subglobose, ostiole central, with protruding papilla. Peridium thin to thick-walled, composed of cell layers, of dark brown to black, thickened, pseudoparenchymatous cells, arranged in a textura angularis. Hamathecium lacking pseudoparaphyses, occasionally with interthecial filaments (Brunneosphaerella). Asci 8-spored, bitunicate, fissitunicate, cylindrical to cylindric-clavate, or ampulliform, sessile to subsessile, apical rounded, thickened, sometimes with distinct ocular chamber. Ascospores 2–3-seriate, or overlapping, ellipsoidal to obclavate, oblong to cylindrical, hyaline to subhyaline or pale yellowish, aseptate or septate, often constrict at the septum, smooth or rough-walled, with small guttules. Asexual morph: Hyphomycetous, cercosporoid and ramularioid fungi, cercospora-, passalora-, pseudocercospora-, pseudocercosporella-, ramularia- and zasmidium-like. Conidiophores single or in group (fascicles), synnematous, or sporodochia. Conidiogenous cells integrated, terminal or intercalary, with holoblastic conidiogenesis.
Type – Ramularia Unger.
Notes – Mycosphaerellaceae is the largest family in Capnodiales, Dothideomycetes containing 127 genera and more than 5,900 species (Videira et al. 2017, Wijayawardene et al. 2018). The family was introduced by Engler & Prantl (1897) with Mycosphaerella as the generic type, initially including 14 genera based on morphological characteristics viz. Achorodothis, Brunneosphaerella, Cymadothea, Euryachora, Gillotia, Melanodothis, Mycosphaerella, Placocrea, Polysporella, Pseudostigmidium, Sphaerellothecium, Sphaerulina, Stigmidium, and Wernerella (Lumbsch & Huhndorf 2010). The family has long been historically discussed based on morphology as well as phylogeny (Crous 2009, Crous et al. 2007a, Hyde et al. 2013, Quaedvlieg et al. 2013, Videira et al. 2017). Phylogenetic studies by Schoch et al. (2006) and Crous et al. (2007a, 2009c) confirmed the phylogenetic affinity of Mycosphaerellaceae in Capnodiales and demonstrated that the mycosphaerella-like sexual morph is polyphyletic forming clades in Mycosphaerellaceae and other closely related families such as Dissoconiaceae, Davidiellaceae and Teratosphaeriaceae (Hyde et al. 2013). Many Mycosphaerella sensu lato have been segregated at the generic level based on differences of their asexual morphs (Crous et al. 2013a, b, Quaedvlieg et al. 2014, Videira et al. 2017). Hyde et al. (2013) re-circumscribed the genera in Mycosphaerellaceae based on morphological studies of the generic types as well as the representative species, coupled with phylogenetic analysis and accepted 46 genera in this family. Subsequent authors have included many genera in Mycosphaerellaceae based on molecular data coupled with morphological characteristics of their asexual morphs (Crous et al. 2016a, b, 2017a, 2019d, Quaedvlieg et al. 2014, Bakhshi et al. 2015, Guatimosim et al. 2016, Videira et al. 2016, 2017, Hyde et al. 2017, Thambugala et al. 2017b, Hassan & Chang 2019). However, the phylogenetic position of many genera in Mycosphaerellaceae are unresolved due to lack of molecular data from the generic types viz. Achorodothis, Anguillosporella, Annellophora, Annellophragmia, Annellosympodia, Camptomeris, Ceratosperma, Cercosperma, Cercosphaerella, Cladosporiella, Clypeispora, Episphaerella, Euryachora, Gillotia, Lembosiopsis, Lophiosphaerella, Melanodothis, Mycoporis, Mycovellosiella, Polysporella, Pseudostigmidium, Sirosporium, Sphaerellothecium and Stigmidium (Videira et al. 2017). Videira et al. (2017) attempted to resolve the phylogenetic relationships of the genera in Mycosphaerellaceae based on phylogenetic analyses of a combined LSU, ITS and rpb-2 sequence dataset. Based on these analyses Videira et al. (2017) introduced 32 additional genera and listed 225 genera in Mycosphaerellaceae. Based on morphological characteristics, Boonmee et al. (2017) placed Episphaerella in Mycosphaerellaceae. Boonmee et al. (2017) excluded Placocrea from Mycosphaerellaceae and treated the genus in Teratosphaeriaceae based on the presence of anastomosing pseudoparaphyses. Wijayawardene et al. (2018) listed 129 genera in Mycosphaerellaceae including Placocrea. We follow the latest treatment and updated accounts of Mycosphaerellaceae in Hyde et al. (2013), Boonmee et al. (2017) and Videira et al. (2017). Videira et al. (2017) placed Acrocladium in Mycosphaerellaceae based only on morphology. However, the generic nomenclature is illegitimate. Hence, we exclude this genus from Mycosphaerellaceae. More than 100 genera were previously treated in Mycosphaerellaceae based only on morphological characteristics and some other genera have also been treated as synonyms of the genera in Mycosphaerellaceae (Hyde et al. 2013, Boonmee et al. 2017, Videira et al. 2017). The generic status of these genera is questionable due to the lack of molecular data of the generic type to confirm their phylogenetic affinities in Mycosphaerellaceae. Hence, we accept 112 genera in Mycosphaerellaceae based on molecular data and the other 107 genera are treated as doubtful genera in Mycosphaerellaceae pending further studies. Detailed notes of the genera mainly can be found in Hyde et al. (2013) and Videira et al. (2017).