Nyl., Flora (Regensburg) 64: 6 (1881)








Collemopsidium Nyl., Flora (Regensburg) 64: 6 (1881)

Type species:

Collemopsidium iocarpum (Nyl.) Nyl., Flora (Regensburg) 64: 6 (1881)

Mycobank number: MB 383526                 Faceoffungi Number:NA

Amphibious marine or freshwater, also terrestrial, lichen-forming fungi with poorly developed endolithic to superficial biofilm-like thallus, light to dark brown or black when epilithic, gelatinous when wet or with black carbonaceous ridges. Photobiont a cyanobacterium (Hyella?). Ascomata perithecioid immersed in the substrate to half-immersed or superficial, globes to subglobose, 100-600 μm diam., with or without an apical to entire involucrellum. Invollucrellum more or less even. Excipulum pale to dark brown. Hymenial gel colourless, I-. Hamathecium of branched and anastomosed pseudoparaphyses, with numerous septa. Asci subcylindrical to ovoid, usually with a short stalk, I-, 8-spored, bitunicate, wall thickened above and ocular chamber. Ascospores 1-septate, hyaline, oblong to fusiform, gelatinous perispore often present, up to 20 μm in length. Conidiomata pycnidia, rare. Conidiospores bacilliform to ellipsoid.


Key references:

Grube M (2005) Frigidopyrenia –a new genus for a particular subarctic lichen, with notes on similar taxa. Phyton 45: 305–318.

Grube M, Hafellner J (1990) Studien an flechtenbewohnenden Pilzen der Sammelgattung Didymella (Ascomycetes, Dothideales). Nova Hedwigia 51: 283–360.

Kohlmeyer J, Hawksworth DL. Volkmann-Kohlmeyer B (2004) Observations on two marine and maritime "borderline" lichens: Mastodia tessellata and Collemopsidium pelvetiae. Mycological Progress 3: 51–56.

Mohr F, Ekman S, Heegaard E (2004) Evolution and taxonomy of the marine Collemopsidium species (lichenized Ascomycota) in north-west Europe. Mycological Research 108: 515–532.

Nordin A (2002) Collemopsidium angermannicum, a widespread but rarely collected aquatic lichen. Graphis Scripta 13: 39–41.

Orange A (2013). British and other pyrenocarpous lichens. Cardiff, Wales: Department of Biodiversity and Systematic Biology, National Museum of Wales. 250 pp.

Pérez-Ortega S, Garrido-Benavent I, Grube M, Olmo R, de los Ríos A. (2016). Hidden diversity of marine borderline lichens and a new order of fungi: Collemopsidiales (Dothideomyceta). Fungal Diversity 80: 285–300.


Key to marine Collemopsidium morphogroups:

1. Thallus superficial, growing on the brown seaweed Pelvetia canaliculata

                                                                                    C. pelvetiae

1. Thallus superficial or endolithic, on mineral substrates                   2

2. Thallus immersed in the substrate                                               3

2. Thallus superficial                                                                      5

3. Perithecia completely immersed in the substrate                          4

3. Perithecia half immersed                           C. pelvetiae morphogroup

4. Involucrellum spreading into the substratum around the ostiolum

                                                                 C. ostrearum morphogroup

4. Involucrellum present or not, but not spreading into the substratum

                                                               C. foveolatum  morphogroup


5. Thallus with black ridges, up to 500 μm high in which the perithecia

are immersed, in the intertidal zone                  C. elegans morphogroup

5. Thallus thin, biofilm-like, brownish, without ridges, usually in the splash

zone                                                             C. halodytes morphogroup

Type & Location:
Other Specimens:
On rocky seashores in the intertidal to the splash zones, on acidic and calcareous substrates, also on animal shells (e.g. barnacles, limpets, periwinkles).
On temperate to high latitudes from both hemispheres, absent in tropical and equatorial regions.
Pertinent Literature:
NOTES: The genus Collemopsidium as currently circumscribed is polyphyletic (Pérez-Ortega et al. 2016). The phylogenetic placement of a number of species occurring in freshwater and terrestrial habitats would require to be confirmed with DNA sequence data. Mohr et al. (2004) studied the taxonomy of marine species in north-west Europe, finding a noticeable genetic diversity. The current number of accepted marine species worldwide (7) largely underestimates the actual number of species which may exceed hundred species (Pérez-Ortega et al. 2016, Pérez-Ortega et al. in prep.). The broad species concepts currently in use correspond in fact too broad morpho groups, which likely include many undescribed species.


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