Fungalpedia – Note 2235, Racodium

 

Racodium Fr.

Citation when using this data: Hongsanan S et al. 2020 – Fungalpedia, Ascomycota.

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

Classification: Racodiaceae, Racodiales, Dothideomycetidae, Dothideomycetes, Pezizomycotina, Ascomycota, Fungi

The black felt-like patches can be seen on extensive parts of rocks. Therefore, the phytosociological name has been given as Racodietum rupestris (Hawksworth et al. 2011). Vainio (1921) listed Coenogonium germanicum as a synonym of R. rupestre. Lepraria and Leproloma species mostly often grow mixed with Racodium rupestre, as well as Cystocoleus ebeneus (Hawksworth et al. 2011). Hawksworth et al. (2011) noted an interesting observation made by W. Watson in 1872-1960 that nitric acid used on a mixed collection of Coenogonium germanicum and Racodium rupestre caused the filament hyphae to twist in Coenogonium germanicum, while the dark hyphae were parallel in Racodium rupestre. Phylogenetic analyses indicated that Racodium rupestre is not close to Cystocoleus ebeneus, but forms a distinct clade within Capnodiales (Muggia et al. 2008, Hawksworth et al. 2011).

Type species: Racodium rupestre Pers., Neues Mag. Bot. 1: 123 (1794).

Other accepted species: Species Fungorum – search Racodium.

 

image

 

Figure 1 – Racodium rupestre (redrawn from Hawksworth et al. 2011). a Filament. b SEM micrographs of filaments. Scale bars: a = 10 μm, b = 2 μm.

 

References

Hawksworth DL, Santesson R, Tibell L. 2011 – Racoleus, a new genus of sterile filamentous lichen-forming fungi from the tropics, with observations on the nomenclature and typification of Cystocoleus and Racodium. IMA Fungus 2, 71–79.

Muggia L, Hafellner J, Wirtz N, Hawksworth DL, Grube M. 2008 – The sterile microfilamentous lichenized fungi Cystocoleus ebeneus and Racodium rupestre are relatives of plant pathogens and clinically important dothidealean fungi. Mycological Research 112, 50–56.

Vainio EA. 1921 – Lichenographia Fennica I. Pyrenolichenes usque proximi Pyrenomycetes et Lichenes Imperfecti. Acta Societatis pro Fauna et Flora Fennica 49, 1–274.

 

Entry by

Sinang Hongsanan, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Science and Oceanography, Shenzhen University, Shenzhen 518060, People’s Republic of China, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand, Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50002, Thailand 

 

Published online 25 March 2026

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