Fungalpedia – Note 2623, Pyrenidium

 

Pyrenidium Nyl. 

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

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

Classification: Pyrenidiaceae, Dothideomycetes families incertae sedis, Pezizomycotina, Ascomycota, Fungi.

The first species, Pyrenidium actinellum, was initially introduced by Nylander (1865) as a lichen species, and the genus was also believed to be established simultaneously. The type species is characterized by a dirty thallus with small spots, entirely black perithecia, 4-spored asci, and tawny or brownish-olive, oblong spores with 3-septate (Nylander 1865). In the original descriptions, the author proposed its specialty that this species differs from Collema species in its pyrenocarpic apothecia and darkened spores but resembles Leptogium in thallus texture. All the species of this genus are lichenicolous with perithecioid ascomata that have blue-green pigment located in upper peridial wall and are immersed to erumpent in host thalli with the upper part exposed or are prominently covered by thalli tissue, sometimes causing gall-like malformations of the host (Hawksworth 1982c, Matzer 1996, Diederich et al. 2018a, Huanraluek et al. 2019). 

Hawksworth (1980a) suggested a close relationship between Dacampiaceae and Pyrenidiaceae, and the later has been considered as a synonym of Dacampiaceae. Crivelli (1983) also suggested that Pyrenidium is similar to Dacampia by having similar ascomatal structures and wall tissues. However, these assumptions were not verified based on phylogenetic analyses until Huanraluek et al. (2019) obtained sequence data from three Pyrenidium species, and these sequences formed a distinct clade far from Dacampiaceae in the phylogenetic analysis. Therefore, the family Pyrenidiaceae was resurrected to accommodate Pyrenidium (Huanraluek et al. 2019).

Type species: Pyrenidium actinellum Nyl. 

Other accepted species: Species Fungorum – search Pyrenidium.

Figure 1 – Pyrenidium actinellum redrawn from Huanraluek et al. (2019). a Appearance of ascomata on host surface. b Vertical section ascomata. c Asci. d Ascospores. Scale bars: a = 500 μm, b = 50 μm, c = 10 μm, d = 5 μm.

 

References

Crivelli P 1983 – Ueber die heterogene Ascomycetengattung Pleospora Rabenh. Eidgenös-sische Technische Hochschule, Doctoral dissertation, 1–215.

Diederich P, Lawrey JD, Ertz D. 2018a – The 2018 classification and checklist of lichenicolous fungi, with 2000 non-lichenized, obligately lichenicolous taxa. The Bryologist 121 (3), 340–425.

Hawksworth DL. 1980a – Notes on some fungi occurring on Peltigera, with a key to accepted species. Transactions of the British Mycological Society 74 (2), 363–386.

Hawksworth DL. 1982c – Secondary fungi in lichen symbioses: Parasites, saprophytes and parasymbionts. Journal Hattori Botanical Laboratory 52, 357–366.

Huanraluek N, Ertz D, Phukhamsakda C, Hongsanan S et al. 2019 – The family Pyrenidiaceae resurrected Mycosphere 10 (1), 634–654.

Matzer M. 1996 – Lichenicolous ascomycetes with fissitunicate asci on foliicolous lichens. Mycological Papers 171, 1–202.

Nylander W. 1865 – Novitatiae quaedum lichenum europaeorum variarum tribuum. Flora (Regensburg) 48 (14), 209–213.

 

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 23 June 2026

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