Berkleasmium longisporum

Berkleasmium longisporum Y.Z. Lu, J.C. Kang & K.D. Hyde

Index Fungorum number: IF 554815; Facesoffungi number: FoF 04698

Etymology: “longisporum” referring to the long helicoid conidia of this fungus

Holotype: MFLU 17–1139

Saprobic on decaying wood in a freshwater stream. Sexual morph: Undetermined. Asexual morph: Hyphomycetous, helicosporous. Colonies on the substratum superficial, effuse, gregarious, brown. Mycelium composed of partly immersed, partly superficial, brown, septate, branched hyphae, with masses of crowded, glistening conidia. Conidiophores macronematous, mononematous, erect, arising as lateral branches from creeping hyphae, cylindrical, 0–3-septate, 15–40 × 5–7 μm, brown, smooth-walled. Conidiogenous cells monoblastic, holoblastic, integrated, sympodial, terminal, cylindrical, truncate at apex, 10–26 μm long, 5–7 μm wide, brown, smooth-walled. Conidia solitary, acrogenous, helicoid, basal cell elongated, rounded at tip, 110–180 μm diam. and conidial filament 11–15 μm wide in the broadest part (x̄ = 145 × 12.5 μm, n = 20), tapering to 4.5–5.5 μm wide near apex and base, 1190–1540 μm long, 100–122-septate, slightly constricted at septa, coiled 2–3 times, becoming loosely coiled or uncoiled in water, brown, smooth-walled. (Descriptions from Lu et al. 2018)

Material examined: THAILAND, Trat, Amphoe Ko Chang, Yuttha Navi Ko Chang Memorial, on submerged decaying wood in a freshwater stream, 27 April 2017, Yong-Zhong Lu, TW08 (MFLU 17–1139, holotype; HKAS 100810, isotype), ex-type living cultures, MFLUCC 17–1999, TBRC; Ibid., TW02 (MFLU 17–1130, paratype), living culture, MFLUCC 17–1990; Ibid., TW11 (MFLU 17–1142 = HKAS 100813, paratype), living culture, MFLUCC 17–2002.

Notes: Berkleasmium longisporum is morphologically similar to Berkleasmium latisporum (Lu et al. 2017, as Neoacanthostigma latisporum) and Berkleasmium thailandicum (Lu et al. 2017, as Neoacanthostigma brunneisporum) in having brown colony with masses of crowded, glistening conidia on natural decaying woody substrate, and 0–3-septate, erect, cylindrical conidiophores, terminal, cylindrical conidiogenous cells with truncate ends on conidial secession, and large-sized helicoid conidia. However, B. longisporum can be easily distinguished by its obviously longer conidia and larger conidial septa (1190–1540 μm long, up to 122-septate) from B. latisporum (540–760 μm long, up to 60-septate) and B. brunneisporum (630–950 μm long, up to 60-septate). (Notes from Lu et al. 2018)

Freshwater distribution: Thailand (Lu et al. 2018)