Parmelina tiliacea parasitized by Marchandiomyces corallinus

Foliose lichen Parmelina tiliacea paratitized by the lichenicolous fungus Marchandiomyces corallinus.

Lichenicolous fungi live exclusively on lichens, most commonly as host-specific parasites, but also as broad-spectrum pathogens, saprotrophs or commensals. Over 1800 species have been described throughout the Ascomycota and Basidiomycota, and estimates are that 3000 species will eventually be described. 95% of described lichenicolous fungi belong to the ascomycetes.

Marchandiomyces corallinus is a Basidiomycota fungus, of the Coticiales order. It has bright pink coralloid sclerotia on dead and dying areas of the host thallus. Widespread and often common on a number of different lichen hosts, especially Parmelia and Physcia species, frequently causing extensive die-back of Parmelia saxatilis on walls and boulders.