Helminthosporium Link, Mag. Gesell. naturf. Freunde, Berlin 3 (1-2): 10 (1809).
= Helminthosporiella Hern.-Restr., Sarria & Crous, in Crous et al., Persoonia 36: 437 (2016).
MycoBank number: MB 8495; Index Fungorum number: IF 8495; Facesoffungi number: FoF 06499; ca. 223 morphological species (Species Fungorum 2020), several species with molecular data.
Type species – Helminthosporium velutinum, Mag. Gesell. naturf. Freunde, Berlin 3(1-2): 10 (1809).
Notes – Helminthosporium was introduced for fungal taxa dominantly reported from wood substrates (Voglmayr & Jaklitsch 2017, Zhao et al. 2018). Species have also been reported as plant pathogens and saprobes on submerged substrates with a worldwide distribution (Kaiser et al. 1979, Semeniuk 1983, Errampalli et al. 2001). Helminthosporium is characterized by its distoseptate conidia, with bud scars at base, hyaline cell on the apex of the conidia (Seifert et al. 2011). The illustration of the sexual morph characters has recently been described by Voglmayr & Jaklitsch (2017). In the phylogenetic analyses (Fig. 42) Helminthosporiella clustered together with Helminthosporium. Helminthosporiella and Helminthosporium have similar morphology of terminal polytretic conidiogenous cells and distoseptate conidia. However, Helminthosporiella only has catenate conidia while Helminthosporium has both terminal and intercalary conidiogenous cells and solitary conidia (Crous et al. 2016b, Voglmayr & Jaklitsch 2017). Based on the morphology and phylogeny evidence, we suggest that Helminthosporiella should be synonymized under Helminthosporium.