Tubeufia rubra Y.Z. Lu, J.C. Kang & K.D. Hyde
Index Fungorum number: IF 554907; Facesoffungi number: FoF 04762
Etymology: “rubra” referring to the red brown colonies on woody substrate.
Holotype: HKAS 7438
Saprobic on decaying wood in a freshwater stream. Sexual morph: Undetermined. Asexual morph: Hyphomycetous, helicosporous. Colonies on the substrate superficial, effuse, gregarious, hyaline on fresh woody substrate, becoming red brown when dried. Mycelium composed of partly immersed, partly superficial, hyaline to dark brown, septate, abundantly branched hyphae, with masses of crowded, glistening conidia. Conidiophores macronematous, mononematous, flexuous, cylindrical, branched, septate, 50–150 μm long, 4.5–6 μm wide, the lower part dark brown and the upper part hyaline to pale brown, smooth-walled. Conidiogenous cells holoblastic, mono- to polyblastic, integrated, sympodial, intercalary, cylindrical, repeatedly geniculate, truncate at apex after conidial secession, 10–19 μm long, 3–4 μm wide, hyaline to pale brown, smooth-walled. Conidia solitary, acropleurogenous, helicoid, rounded at tip, 35–50 μm diam. and conidial filament 3–5 μm wide (x̄ = 45 × 4.5 μm, n = 20), 230–370 μm long, tightly coiled 2–3½ times, becoming loosely coiled in water, indistinctly multi-septate, guttulate, hyaline to pale brown, smooth-walled. (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, obviously umbonate, with rough surface, veined and wrinkle, edge entire, reaching 16 mm in 2 weeks at 28 °C, 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, 14 May 2016, Yong-Zhong Lu, PF02–2 (HKAS 7438, holotype; GZAAS 16–0093, isotype), ex-type living culture, GZCC 16–0081; Ibid., PF06 (GZAAS 16–0095, paratype), living culture, GZCC 16–0083.
Notes: Tubeufia rubra is morphologically distinct from other helicosporous hyphomycetes by its colonies on natural substrate which are hyaline first and becoming red brown when dried. Its conidia are similar to T. chiangmaiensis but can be distinguished by conidiophore morphology. Phylogenetically, our two isolates of T. rubra formed one clade and shares a sister relationship to T. inaequalis with high bootstrap support, and support that they are distinct species. (Lu et al. 2018)
Freshwater distribution: China (Lu et al. 2018)