Fungalpedia – Note 3096, Hyalohelicoon

 

Hyalohelicoon J. Ma, K.D. Hyde & Y.Z. Lu.

Citation when using this data: Jian Ma et al. 2024 – Fungalpedia.

Index Fungorum, Faceoffungi, MycoBank, GenBank, Fig 1.

Classification: Tubeufiaceae, Tubeufiales, Incertae sedis, Dothideomycetes, Pezizomycotina, Ascomycota, Fungi.

Etymology: “Hyalo-’’ refers to hyaline conidia of this genus, ‘‘-helicoon’’ refers to its morphology similar to Helicoon on natural woody substrate.

Saprobic on submerged decaying wood in a freshwater habitat. Sexual morph Undetermined. Asexual morph Hyphomycetous, helicosporous. Colonies on natural substrate superficial, effuse, solitary, scattered or gregarious, white. Mycelium partly immersed, partly superficial, composed of hyaline, smooth hyphae. Conidiophores micronematous, arising from hyphae, hyaline to pale brown, smooth-walled. Conidiogenous cells truncate at apex after conidial secession, hyaline, smooth-walled. Conidia solitary, acrogenous, helicoid, circinate in three dimensions, rounded at apex, tapering towards apex and base, tightly coiled several times in a clockwise direction to form loosely coiled in water, multi-septate, verruculose, hyaline, smooth-walled.

Notes: Herein, we establish a new genus, Hyalohelicoon, to accommodate a new taxon, H. multiseptatum, as the type species. Hyalohelicoon resembles the structure of helicoon-like species on the surface of natural woody substrates (Morgan 1892; Linder 1929). However, Hyalohelicoon can be easily distinguished from Helicoon species by its distinct conidiophores formed on hyphae, and different conidial morphologies, such as being tightly coiled several times in a clockwise direction but becoming loosely coiled or uncoiled, and fragile in water (Morgan 1892; Linder 1929; Voglmayr 1997a; Goh and Kuo 2018; Lu et al. 2018b). On the other hand, the conidia of other helicoon-like species are tightly coiled several times in a clockwise direction, but become subglobose or broadly elliptical bodies in water (Goh and Hyde 1996; Goh and Kuo 2018; Lu et al. 2018b; Linder 1929).

Type species: Hyalohelicoon multiseptatum J. Ma, K.D. Hyde & Y.Z. Lu.

Other accepted species: Species Fungorum – search Hyalohelicoon.

Figure 1 – Hyalohelicoon multiseptatum (HKAS 131092, holotype). a–c Colonies on decaying wood. d Conidiophores and conidiogenous cells. e–n Conidia. Scale bars: g–i, l–n = 50 µm, j, k = 40 µm, d–f = 20 µm

 

References

Goh TK, Hyde KD. 1996 – Biodiversity of freshwater fungi. Journal of Industrial Microbiology and Biotechnology 17(5-6):328–345.

Goh TK, Kuo CH. 2018 – A new species of Helicoön from Taiwan. Phytotaxa 346(2):141–156.

Linder DH. 1929 – A monograph of the helicosporous fungi imperfecti. Annals of the Missouri Botanical Garden 16(3):227–388.

Lu YZ, Liu JK, Hyde KD, Jeewon R et al. 2018b – A taxonomic reassessment of Tubeufiales based on multi-locus phylogeny and morphology. Fungal Diversity 92:131–344.

Morgan AP. 1892 – North american helicosporae. Journal of the Cincinnati Society of Natural History 15.

Voglmayr H. 1997a – Helicodendron praetermissum sp. nov. and Spirosphaera carici-graminis sp. nov., aero-aquatic fungi on monocotyledonous debris. Canadian Journal of Botany 75(10):1772–1777.

 

Entry by

Jian Ma, School of Food and Pharmaceutical Engineering, Guizhou Institute of Technology, Guiyang 550003, P.R. China, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand, School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand.

 

Published online 3 September 2026

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