Tubeufia xylophila (P.N. Singh & S.K. Singh) Y.Z. Lu & K.D. Hyde
≡ Helicosporium xylophilum P.N. Singh & S.K. Singh [as ‘xylophilous’], Current Research in Environmental & Applied Mycology 6(4): 251 (2016)
Index Fungorum number: IF 554918; Facesoffungi number: FoF 04767
Saprobic on decaying wood in a freshwater stream. Sexual morph: Undetermined. Asexual morph: Hyphomycetous, helicosporous. Colonies on the substratum superficial, effuse, gregarious, white to pale brown. Mycelium composed of partly immersed, partly superficial, hyaline to pale brown, septate, abundantly branched hyphae, with masses of crowded, glistening conidia. Conidiophores macronematous, mononematous, flexuous, cylindrical, unbranched, septate, 25–75 μm long, 4.5–5.5 μm wide, hyaline to pale brown, smooth-walled. Conidiogenous cells holoblastic, mono- to polyblastic, integrated, sympodial, intercalary or terminal, cylindrical, repeatedly geniculate, truncate at apex after conidial secession, 10–21 μm long, 4–5 μm wide, hyaline to pale brown, smooth-walled. Conidia solitary, acropleurogenous, helicoid, rounded at tip, 30–40 μm diam. and conidial filament 3–5.5 μm wide (x̄ = 36 × 4.5 μm, n = 20), 185–295 μm long, coiled 2½–3 times, becoming loosely coiled in water, indistinctly multi-septate, guttulate, hyaline. (Lu et al. 2018)
Culture characteristics: Conidia germinating on water agar and germ tubes produced from conidia within 12 h. Colonies growing on PDA, circular, with flat surface, edge entire, reaching 20 mm in 3 weeks at 28 °C, pale brown to brown in PDA medium. Mycelium superficial and partially immersed, branched, septate, hyaline to pale brown, smooth.
Material examined: CHINA, Guangxi Province, Fangchenggang City, on submerged decaying wood in a freshwater stream, 15 May 2016, Yong-Zhong Lu, JHC03–1 (HKAS 97422, reference specimen designated here; GZAAS 16–0044), living cultures, MFLUCC 17–1520 = GZCC 16–0032; Ibid., JHC07–3 (GZAAS 16–0050), living culture, GZCC 16–0038.
Notes: Our two collections morphologically resemble Helicosporium xylophilous, indroduced by Singh and Singh (2016) and therefore, we confirmed them as the same species. However, its morphology does not tally with those of Helicosporium but fits into Tubeufia. This taxon resembles Tubeufia cylindrothecia in conidiophore and conidial morphology but can be distinguished by its mono- to polyblastic, intercalary or terminal conidiogenous cells while T. cylindrothecia have unbranched conidiophores and monoblastic, terminal conidiogenous cells (Luo et al. 2017). Phylogentically, our two isolates share a sister relationship to T. sympodihylospora with high bootstrap support and, therefore, we synonymize this taxon as Tubeufia xylophila. As the holotype of this fungus is available but lacks molecular data, we designate our new collection HKAS 97422 as a reference specimen. (Lu et al. 2018)
Freshwater distribution: China (Lu et al. 2018)