Fungalpedia – Note 2900, Refractohilum

 

Refractohilum D. Hawksw. 

Citation when using this data: Meng QF et al. – Fungalpedia.

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

Classification: Ascomycota genera incertae sedis, Fungi.

Refractohilum was introduced by Hawksworth (1977a) to include three lichenicolous species: the newly described R. galligenum and two combinations, R. achromaticum and R. peltigerae. However, R. achromaticum was transferred to Gyalectiphila achromatica (B. Sutton) Cl. Roux & Diederich, and R. peltigerae to Hawksworthiana peltigerae (Keissl.) Diederich (Diederich et al. 2024). The genus is characterized by lichenicolous fungi forming effuse, hair-like colonies, with predominantly immersed mycelium. The conidiophores are erect, unbranched, hyaline, and sparsely septate. Conidiogenous cells are terminal, exhibiting percurrent proliferation with distinctive annellations. Conidia are cymbiform, hyaline, smooth-walled, and non-catenate, featuring 0–3 septa, an obtuse apex, and a thick, refractive, truncate base (Hawksworth 1977a).

Roux et al. (1997) described two additional species, R. intermedium and R. pluriseptatum, associated with Pachyphiale carneola, however, the two species were later transferred to Gyalectiphila by Diederich et al. (2024). Subsequently, Castañeda Ruíz et al. (1998) introduced R. mycophilum, a fungicolous species found on the apothecia of Xylaria. Initially placed in Moniliaceae (Deuteromycotina-Hyphomycetes), Refractohilum is now tentatively classified within Ascomycota genera incertae sedis due to the absence of molecular data (Hyde et al. 2024).

Type species: Refractohilum galligenum D. Hawksw., on Nephroma laevigatum (Hawksworth 1977a)

Other accepted species: Species Fungorum – search Refractohilum.

Figure 1 – Refractohilum galligenum redrawn from Hawksworth (1977a). a Conidiogenous cells. b Conidia. Scale bars: a, b = 10 μm.

 

References

Castañeda Ruíz R, Kendrick B, Guarro J. 1998 – Notes on conidial fungi. XVIII. New species of Pseudomicrodochium and Refractohilum from rainforest litter. Mycotaxon 68, 23–32.

Diederich P, Ertz D, Braun U 2024 – Flora of lichenicolous fungi, Vol. 2, Hyphomycetes. National Museum of Natural History, Luxembourg, 2, 1–544.

Hawksworth DL. 1977a – Three new genera of lichenicolous fungi. Botanical Journal of the Linnean Society 75 (2), 195–209.

Hyde KD, Noorabadi M, Thiyagaraja V, He M et al. 2024 – The 2024 Outline of Fungi and fungus-like taxa. mycosphere 15, 5146–6239.

Roux C, Bricaud O, Coeur DL, Etayo J. 1997 – Les Refractohilum (Hyphomycètes, Moliniacés) à conidies pluriseptées en Europe et au Canada. Canadian journal of botany 75 (9), 1592–1600.

 

Entry by

Meng QF, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai, 57100, Thailand and School of Public Health, Zunyi Medical University, Guizhou 563000, China.

 

Published online 5 August 2026

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