Pleosporales » Massarinaceae » Helminthosporium

Helicohyalinum infundibulum

Helicohyalinum infundibulum Y.Z. Lu, J.K. Liu & K.D. Hyde

Index Fungorum number: IF 554834; Facesoffungi number: FoF 04711

Etymology: “infundibulum” referring to the inverted funnel shape of conidiogenous cells of this fungus.

Holotype: HKAS 100826


Saprobic on submerged decaying wood in a freshwater stream. Sexual morph: Undetermined. Asexual morph: Hyphomycetous, helicosporous. Colonies on the substratum superficial, effuse, gregarious, white. Mycelium composed of partly immersed, partly superficial, hyaline, septate, branched hyphae, with masses of crowded, glistening conidia. Conidiophores macronematous, mononematous, flexuous, 0–3-septate, unbranched or branched, cylindrical, 25–40 μm long, 4–5 μm wide, hyaline, smooth-walled. Conidiogenous cells integrated, terminal, cylindrical, tapering towards apex, inverted funnel at apex, 9–24 μm long, 3.5–4.5 μm wide, hyaline, smooth-walled. Conidia solitary, acrogenous, helicoid, hygroscopic, rounded at the tip, 40–50 μm diam. and conidial filament 6.5–8.5 μm wide in the broadest part ( = 44 × 7.5 μm, n = 20), tapering to 3.5–4.5 μm wide near apex and the base, 250–330 μm long, tightly coiled 2½–3½ times, not becoming loose in water, 40–45-septate, soft, easily deforming and fracturing, hyaline, 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, irregular, with flat surface, edge undulate, reaching 9 mm in 3 weeks at 28 °C, brown to dark brown in PDA medium. Mycelium superficial and partially immersed, branched, septate, hyaline to pale brown, smooth.


Material examined: THAILAND, Chiang Rai, Muang, Ban Nang Lae Nai, on submerged decaying wood in a freshwater stream, 28 November 2015, Saranyaphat Boonmee and Yong-Zhong Lu, TUB03–5 (HKAS 100826, holotype), ex-type living cultures, MFLUCC 16–1133, TBRC 8910.


Notes: Morphologically, Helicohyalinum infundibulum resembles Helicohyalinum aquaticum in having short conidiophores and terminal monoblastic conidiogenous cells with an inverted funnel shape but can be distinguished by its conidia features. The conidia of H. infundibulum are tightly coiled 2½–3½ times that are not loose in water, but the conidia of H. aquaticum become loosely coiled or uncoiled in water. Besides, the conidia of H. infundibulum are smaller in size than H. aquaticum (40–50 μm vs. 62–89 μm diam.). Phylogenetically, H. infundibulum shares a sister relationship to H. aquaticum with high bootstrap support (100% MLBS, 1.00 PP), and the topology of our phylogenetic tree shows that they are distinct species. (Notes from Lu et al. 2018)