Biscogniauxia nummularia

Biscogniauxia nummularia is a plant pathogen in the family Graphostromataceae, known as the beech tarcrust.^[1] The specific epithet is derived from the Latin "nummus" meaning a coin, referring to the often rounded and coin-like encrustations.

Biscogniauxia nummularia
Scientific classification
Domain:	Eukaryota
Kingdom:	Fungi
Division:	Ascomycota
Class:	Sordariomycetes
Order:	Xylariales
Family:	Graphostromataceae
Genus:	Biscogniauxia
Species:	B. nummularia
Binomial name
Biscogniauxia nummularia (Bull.) Kuntze (1891)
Synonyms
Biscogniauxia bulliardii (Tul. & C.Tul.) Kuntze Hypoxylon nummularium Bull. (1790) Hypoxylon nummularium var. nummularium Bull. Kommamyce bulliardii (Tul. & C.Tul.) Nieuwl. Nummularia anthracina (J.C.Schmidt) Traverso Nummularia bulliardii Tul. & C.Tul. Nummularia nummularia (Bull.) J.Schröt. Numulariola nummularia (Bull.) House Sphaeria anthracina J.C.Schmidt Sphaeria nummularia DC.

Description

The fruit body forms a thick and shiny black crust, on beech (Fagus) bark and is found at all times of the year. It is not edible.^[1] Young specimens are covered by a light brown outer layer. The spores are black to dark brown.

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  Detail of the tarcrust's structure
• 
  Beech tarcrust growth
• 
  Encrustations on beech bark

Distribution

Biscogniauxia nummularia is a common pathogen specific for Beech trees, and has been recorded throughout Europe and Russia.^[2]

Environmental impact

The decline of European beech (Fagus sylvatica) in Sicily and Calabria (Italy) has been linked to B. nummularia and experiments have suggested that this ascomycete plays a primary pathogenic role under certain environmental conditions.^[3] It typically causes strip-cankering and general wood decay.^[4]