''Bryostigma epiphyscium'' is a species of

lichenicolous fungus A lichenicolous fungus is a parasitic fungus that only lives on lichen as the host. A lichenicolous fungus is not the same as the fungus that is the component of the lichen, which is known as a lichenized fungus. They are most commonly specific t ...

in the order

Arthoniales The Arthoniales is the second largest order of mainly crustose lichens, but fruticose lichens are present as well. The order contains around 1500 species, while the largest order with lichenized fungi, the Lecanorales, contains more than 14000 s ...

. Formerly classified in the genera ''

Arthonia ''Arthonia'' is a genus of lichens in the family Arthoniaceae. It was circumscribed by Swedish botanist Erik Acharius in 1806. It is a genus of thin crustose lichen of widely varying forms, commonly called comma lichens.Field Guide to Californi ...

'' and '' Conida'', it was transferred to the genus ''

Bryostigma ''Bryostigma'' is a genus of lichen-forming fungi of uncertain familial placement in the order Arthoniales. The genus was circumscribed in 1979 by Josef Poelt and Peter Döbbeler, with the muscicolous lichen '' Bryostigma leucodontis'' assigne ...

'' in 2020. It is known to infect the lichen ''

Physcia caesia ''Physcia caesia'', known colloquially as blue-gray rosette lichen and powder-back lichen, is a species of foliose lichenized fungus. First described by Georg Franz Hoffmann in 1784, it is common across much of Europe, North America and New Z ...

'' and other lichens of the genus ''

Physcia ''Physcia'' is a genus of lichenized fungi in the family Physciaceae. The genus name means "inflated" or "sausage-like", referring to the form of the type species. According to a 2008 estimate, the widespread genus contains 73 species. Species ...

''.

References

Arthoniomycetes Fungi of Iceland Fungi described in 1875 Taxa named by William Nylander (botanist) Lichenicolous fungi {{Arthoniomycetes-stub