Helminthosporiella Konta & K.D. Hyde, gen. nov.

Index Fungorum number: IF558311; Facesoffungi number: FoF09171

Helminthosporiella Hern.-Restr., Sarria & Crous, in Crous et al., Persoonia 36: 437 (2016), MycoBank MB816988, Nom. inval., Art. 40.3 (Shenzhen)

Saprobic on dead petiole of Cocos nucifera.

Sexual morph: Undetermined.

Asexual- morph: Colony on natural substrate black, hairy. Mycelium mostly immersed, at the surface forming small stroma-like aggregations of dark brown pseudoparenchymatous cells. Coni- diophores macronematous, wide at the apex and base, arising singly from the stroma cells, erect, simple, unbranched, straight or flexuous, thick-walled, cylindrical, smooth-walled, dark brown, becoming pale brown at the apex, septate. Conidiogenous cells terminal and intercalary, polytretic, with well-defined thick, pale brown pores. Conidia obpyriform to lageniform, straight or curved, smooth-walled, subhyaline to light brown, distoseptate, with a thick scar at the base.

Type species:—Helminthosporiella stilbacea Konta & K.D. Hyde

Notes: –  Helminthosporiella was introduced by Crous et al. [63] to accommodate a new combination of Hel. stilbacea Hern.-Restr., Sarria & Crous, in Massarinaceae, the basionym of the type species was not provided a Latin diagnosis [63]. In this paper we accept Helminthosporiella as a distinct genus, presently with a single species Helminthosporiella stilbacea. Since a Latin diagnosis is no longer required, we provide an English diagnosis and priority was given to the previous genus and species names. Furthermore, this study provides the holotype to validate the genus and species, and reports the first host record of Hel. stilbacea associated with coconut tree (Arecaceae) in Thailand. In particular, based on the present morphology and DNA sequence data, Helminthosporiella is identified as a monotypic genus, with Hel. stilbacea as the type species. The members of Helminthosporiella were found associated with leaf spots on oil palm (Arecaceae) [64].