Fungalpedia – Note 3126, Helicoon
Helicoon Morgan, J. Cincinnati Soc. Nat. Hist. 15 (1): 49 (1892).
Citation when using this data: Jian Ma et al. 2024 – Fungalpedia.
Index Fungorum, Faceoffungi, MycoBank, GenBank, Fig 1.
Classification: Arthrobotryaceae, Orbiliales, Orbiliomycetidae, Orbiliomycetes, Pezizomycotina, Ascomycota, Fungi.
Notes: Helicoon was established by Morgan (1892), with H. sessile as the type species based on its nonproliferating, ellipsoidal to doliiform conidia. Index Fungorum (2024) records 28 species of Helicoon; among these H. farinosum, H. fuscosporum, H. gigantisporum, H. ovalisporum, H. richonis, H. spirale, H. subglobosum, H. thaxteri, H. thysanophorum, and H. tubulosum were transferred to Helicoascotaiwania, Helicocephalum, Helicodendron, Helicomyces, Helicorhoidion, Lambertella, Magnohelicospora, Pleohelicoon, and Pseudohelicoon (Index Fungorum 2024; Goh and Kuo 2018). Helicoon elegans, H. fairmanii and H. reticulatum are currently known as Pleohelicoon richonis, Helicoon sessile, and Helicoon ellipticum, respectively (Goh and Kuo 2018). To date, Helicoon comprises thirteen species, namely H. auratum, H. chlamydosporum, H. dendroides, H. doliiformis, H. ellipticum, H. macrosporum, H. maioricense, H. microsporum, H. myosuroides, H. peruamazonense, H. pluriseptatum, H. septatissimum and H. sessile, which were found on dead wood and soil from both freshwater and terrestrial habitats (Morgan 1892; Saccardo 1906; Linder 1929; Van Beverwijk 1954; Abdullah 1980; Goos et al. 1986; Matsushima 1993; Van and Samson 1994; Abdullah et al. 1996, 1998; Godeas and Arambarri 1996; Pfister 1997; Voglmayr 1997a; Chang 2001; Goh and Kuo 2018; Vu et al. 2019). Additionally, based on Linder’s limited description, Goos considered the establishment of H. politulum as uncertain (Linder 1929; Goos et al. 1986; Goh and Kuo 2018). Based on morphological comparison, Pfister (1997) suggested that Helicoon sessile is the asexual form of Orbilia luteorubella. Later, LSU molecular data confirmed that Helicoon sessile (A327) formed a distinct clade from Orbilia luteorubella (6610) and O. luteorubella (690) within Orbiliaceae (Orbiliales) (Goh and Kuo 2018). However, based on a pairwise nucleotide comparison of LSU, Helicoon sessile (A327) differs from Orbilia luteorubella (6610) in 31/627 bp (4.9%), and from Orbilia luteorubella (690) in 30/627 bp (4.8%), respectively. Therefore, we conclude that Helicoon sessile (A327) differs from Orbilia luteorubella. Additional molecular data and morphological characteristics are needed to verify their taxonomic status. At the same time, we excluded Orbilia piloboloide from helicosporous taxa within Orbiliaceae (Orbiliales) based on its small, curved, or irregularly shaped conidia (Pfister 1997; Lu and Kang 2020). Helicodendron resembles Helicoon in producing ellipsoidal, helicoid conidia but can easily be distinguished in having ovoid, helicoid conidia with chains (Linder 1929).
Type species: Helicoon sessile Morgan, Journal of the Cincinnati Society of Natural History 15 (1): 49 (1892).
Other accepted species: Species Fungorum – search Helicoon.
Figure 1 – (a) Halenospora varia (redrawn from Seifert et al. (2011)); (b) Helicoon sessile (redrawn from Seifert et al. (2011)); (c) Neocirrenalia nigrospora (redrawn from Yang et al. (2023)). a, c Conidiophore with attached conidia. b Conidiophores. d conidia. Scale bars: a–d = 30 μm; (d) Illosporiopsis christianse (redrawn from Seifert et al. (2011)).
References
Goh TK, Kuo CH. 2018 – A new species of Helicoön from Taiwan. Phytotaxa 346(2):141–156.
Goh TK, Kuo CH. 2018 – A new species of Helicoön from Taiwan. Phytotaxa 346(2):141–156.
Goos R. 1986– A review of the anamorph genus Helicoma. Mycologia 78(5):744–761.
Lu B, Hyde K, Ho W, Tsui K et al. 2000 – Checklist of Hong Kong fungi. Fungal Diversity Press, Hong Kong.
Matsushima T. 1993 – Matsushima mycological memoirs no. 7. Matsushima Fungus Collection, Kobe, Japan.
Morgan AP. 1892 – North american helicosporae. Journal of the Cincinnati Society of Natural History 15.
Pfister DH. 1997 – Castor, Pollux and life histories of fungi. Mycologia 89(1):1–23.
Saccardo PA. 1906 – Notae mycologicae. Series VII. Annales Mycologici 4(3):273–278.
Van der AA HA, Samson RA. 1994 – A new species of Helicoon. Mycological Research 98(1):74–76.
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 10 September 2026