Neohelicomyces guizhouensis J. Ma, Y. Z. Lu & K. D. Hyde

Neohelicomyces guizhouensis J. Ma, Y. Z. Lu & K. D. Hyde, MycoKeys 105: 323 (2024) Fig. 4 Description. Saprobic on dead wood of Phellodendron amurense. Sexual morph Undetermined. Asexual morph Hyphomycetous, helicosporous. Colonies on natural substrate superficial, effuse, gregarious, with mass of crowded conidia, white. Mycelium partly immersed, partly superficial, composed of hyaline to pale brown, branched, septate, guttulate, smooth hyphae. Conidiophores 154–175 × 4–5 μm (x ̄ = 161 × 4.5 μm, n = 20), macronematous, mononematous, erect, cylindrical, tapering towards the apex, straight or slightly flexuous, unbranched, septate, subhyaline to pale brown, thick-walled. Conidiogenous cells 11–19 × 2.5–4 μm (x ̄ = 14.5 × 3.5 μm, n = 20), holoblastic, monoblastic or polyblastic, integrated, terminal or intercalary, cylindrical, with denticles, subhyaline to pale brown, smooth-walled. Conidia solitary, acropleurogenous, helicoid, developing on tooth-like protrusion, 14–20 μm diam. and conidial filament 1.5–3 μm wide (x ̄ = 16 × 2 μm, n = 20), 94–133 μm long (x ̄ = 113 μm, n = 25), tightly coiled 3–3 ½ times, not becoming loose in water, guttulate, hyaline, smooth-walled. Culture characteristics. Conidia produce germ tubes on PDA within 10 hours of incubation at 25 ° C. Colonies on PDA are circular, with a raised centre and undulate edge, reaching a diameter of 30 mm after 45 days of incubation at 25 ° C. The colony appears grey to pale brown on the top view, with the reverse side ranging from pale brown to brown. Material examined. China • Guizhou Province, Guiyang City, Qingzhen City, Maige Miao and Bouyei Ethnic Township, Xiaochong Village, 26°74′N, 106°37′E, on the rotting branch of Phellodendron amurense, 1 October 2024, Shi-Ping Zou, HB-Z 15-1 (HKAS 145881), living culture GZCC 25-0007 • Ibid., HB-Z 15-2 (HKAS 145880), living culture GZCC 25-0008. Notes. Phylogenetic analysis showed that our isolates (GZCC 25-0007 and GZCC 25-0008) grouped with N. guizhouensis (GZCC 23-0725) by strong support (ML / PP = 98 % / 0.97; Fig. 1). Pairwise comparison of the ITS, LSU, tef 1 - α and rpb 2 sequences between GZCC 25-0007 and N. guizhouensis (GZCC 23-0725) revealed minimal nucleotide differences: 5 bp / 424 bp (1.2 %, including two gaps), 3 bp / 859 bp (0.3 %, including two gaps), 2 bp / 892 bp (0.2 %, no gaps) and 2 bp / 903 bp (0.2 %, no gaps), respectively. Morphologically, our new collections share identical characteristics of conidiogenous cells and conidia with the holotype of N. guizhouensis (Ma et al. 2024 a). Therefore, GZCC 25-0007 and GZCC 25-0008 are identified as N. guizhouensis. Neohelicomyces guizhouensis was originally described by Ma et al. (2024 a) from submerged wood in a stream in China and our study represents its first record associated with Phellodendron amurense.