Unveiling four new taxa and Nigrosynnema natarajanensis comb. nov. in Stachybotryaceae (Hypocreales) from monocotyledon plants in Guangdong Province, China

Members of Stachybotryaceae are distributed worldwide, with certain species playing a significant role as bio-degraders and some causing diseases in plants, humans, and animals. Other species within this family can be found in soil and have been reported as saprobes in various plants. In this study (2021-2022), fungal taxa resembling Stachybotryaceae, isolated from dead leaves of <i>Agavesisalana</i> and a dead stem of <i>Wurfbainiavillosa</i> in Guangdong Province, China, are identified based on morphological characteristics and molecular data. Multi-locus phylogeny based on calmodulin (<i>cmdA</i>), internal transcribed spacer (ITS), the large subunit nuclear rDNA (LSU), RNA polymerase II second largest subunit (<i>rpb2</i>), the partial translation elongation factor 1-α (<i>tef1-α</i>), and β-tubulin (<i>tub2</i>) revealed that nine strains were grouped within Stachybotryaceae. <i>Nigrosynnemaguangdongense</i> <b>gen. et sp. nov.</b>, typical of Stachybotryaceae but having unusual olivaceous brown to black synnemata that are narrower towards the apex and produce phialidic, aseptate, slimy conidia in black and glistening heads, is introduced. Additionally, <i>Brevistachyswurfbainiae</i> and <i>Sirastachysguangdongensis</i> are introduced as new species. <i>Stachybotrysmicrosporus</i> is a new host record for <i>Agavesisalana</i>. The present study provides comprehensive descriptions, illustrations, and molecular data analyses of the newly discovered taxa and newly recorded species as a taxonomic and phylogenetic contribution to Stachybotryaceae. Furthermore, a new combination, <i>Nigrosynnemanatarajanensis</i>, is proposed for the previously described <i>Virgatosporanatarajanensis</i>.