Abstract:
Palms (Arecaceae) are substrates for a highly diverse range of fungi. Many species are
known as saprobes and many are important plant pathogens. Over the course of our studies of micro-
fungi from palms in Thailand, two new taxa were discovered. Morphological characteristics and
phylogenetic analyses of combined ITS, LSU, SSU, and tef1-α sequence data revealed their taxonomic
positions within Massarinaceae. There are currently ten genera identified and accepted in Massari-
naceae, with the addition of the two new genera of Haplohelminthosporium and Helminthosporiella, that
are introduced in this paper. Each new genus is provided with a full description and notes, and each
new taxon is provided with an illustration for the holotype. A list of identified and accepted species
of Helminthosporium with morphology, host information, locality, sequence data, and related refer-
ences of Helminthosporium reported worldwide is provided based on records in Species Fungorum
2021. This work provides a micro-fungi database of Haplohelminthosporium, Helminthosporiella, and
Helminthosporium which can be modified and validated as new data come to light.
