Tubeufia cylindrothecia (Seaver) Höhn.
Basionym: Ophionectria cylindrothecia Seaver, Mycologia 1(2): 70 (1909)
Saprobic on decaying wood in terrestrial and freshwater habitats. Sexual morph: Undetermined. Asexual morph: Colonies superficial, effuse, gregarious, white to pale brown. Mycelium composed of partly immersed, hyaline to pale brown, septate, sparsely branched hyphae, with masses of conidia. Conidiophores 60–140 × 3–5 μm (x̄ = 108 × 3.8 µm, n = 10), macronematous, mononematous, cylindrical, septate, branched or unbranched, erect, flexuous, pale brown to brown, smooth-walled. Conidiogenous cells 10.5–18 × 3.5–4 μm (x̄ = 15.5 × 3.8 µm, n = 5), holoblastic, mono- to poly-blastic, integrated, terminal, smooth, truncate at the apex after conidial secession, each with single or several conidia. Conidia solitary, acrogenous, helicoid, rounded at tip, 24.5–28 μm diam. and conidial filament 3–4.2 μm wide (x̄ = 26 × 3.6 μm, n = 10), 100–210 μm long, coiled 2.75–3.25 times, indistinctly multi-septate, guttulate, hyaline to pale brown, smooth-walled. (Dong et al. 2020)
Culture characteristics: On PDA, colony irregular, dark brown to black from above and below, surface rough, with dense superficial or immersed mycelium, most mycelium immersed in medium, dry, edge undulate.
Material examined: THAILAND, Chiang Mai Province, on submerged wood in a stream, 29 November 2010, H. Zhang, d6 (MFLU 11-0969), living culture MFLUCC 10-0919; ibid., d29 (MFLU 11-1107), living culture MFLUCC 11-0076.
Notes: Our two new collections MFLUCC 10-0919 and MFLUCC 11-0076 are identified as Tubeufia cylindrothecia based on the identical ITS and LSU sequence data to the ex-type strain of T. cylindrothecia, and phylogenetic analysis (Dong et al. 2020). The asexual morph of T. cylindrothecia was first reported by Luo et al. (2017) and later encountered by Lu et al. (2018) from freshwater habitats. Our freshwater collections have longer conidiophores (60–140 μm vs. 50–81 μm) and shorter conidia (100–210 μm vs. 256–314 μm) than the holotype (Luo et al. 2017). Additionally, we found polyblastic conidiogenous cells in MFLU 11-0969, while they are only monoblastic in the holotype (Luo et al. 2017).
Freshwater distribution: China (Luo et al. 2017), Thailand (Lu et al. 2018; Dong et al. 2020)