Major Groups > Crust Fungi > Biscogniauxia atropunctata


Biscogniauxia atropunctata

[ Ascomycota > Sordariomycetes > Xylariales > Biscogniauxia . . . ]

by Michael Kuo

Appearing in spring and early summer in oak-based forests east of the Rocky Mountains, this subtly beautiful crust fungus spreads across standing and fallen logs in bluish gray patches. The surface of the fungus is hard and, from a distance, appears smooth—but on close examination is punctuated with many tiny, pimply black dots. At maturity Biscogniauxia atropunctata is more white than gray, and has lost its bluish shades. Eventually, the patches become blackened.

Hypoxylon atropunctatum is a synonym.


Ecology: Saprobic on the deadwood of oaks and other hardwoods; causing a white rot; probably widely distributed east of the Rocky Mountains. The illustrated and described collections are from Illinois.

Fruiting Body: Spreading in resupinate patches ranging from a few cm across to quite large (nearly a meter), irregular in outline; surface bluish gray to purplish gray when fresh and young, maturing to nearly white, covered with tiny black dots; eventually becoming blackened overall; less than 1 mm thick; flesh black and very tough.

Odor: Not distinctive.

Microscopic Features: Spores 24–32 x 12–15 µm; fusiform to sublimoniform or subellipsoid; with a single longitudinal germ slit extending the length of the spore; smooth; very dark brown to black in KOH. Asci cylindric; with amyloid tips.

REFERENCES: (Schweinitz, 1822) Pouzar, 1979. (Ju & Rogers, 2001; Vasilyeva et al., 2007; Binion et al., 2008; Beug et al., 2014; Woehrel & Light, 2017.) Herb. Kuo 04261401.

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Biscogniauxia atropunctata

Biscogniauxia atropunctata

Biscogniauxia atropunctata

Biscogniauxia atropunctata

Biscogniauxia atropunctata

Biscogniauxia atropunctata

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Kuo, M. (2019, April). Biscogniauxia atropunctata. Retrieved from the MushroomExpert.Com Web site: