Willow Bracket

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not listed

not listed

Willow Bracket is common and widespread fungus. It occurs in Europe, Asia, and North America, and has few scattered records south of the equator. It is common in Minnesota. It causes white trunk rot on hardwood trees. It turns the wood into a soft, white, spongy mass. It infects twenty-one genera of hardwoods. It is most common on willow, but it also infects birch, poplar, alder, apple, ash, black walnut, buckthorn, cherry, hazel, ironwood, maple, and mountain ash.

The fruiting body (conk) is a 2″ to 8″ wide, ¾″ to 4¾″ thick polypore. It is hoof-shaped, rounded and curved downward on top, flat or slightly angled upward below. There is no stalk.

The upper surface is brown and hairy when young, soon becoming gray and hairless. Older specimens are black and often cracked. The margin is brown and velvety on actively growing conks.

The underside is light or dark brown. The pore tubes are distinctly layered (stratified), one layer developing each year. Older layers often become buried.

The flesh is hard, woody, and dark brown or rusty brown. When cut in cross section there are white lines (mycelial threads) running through the flesh and older, buried tubes.

An individual conk can survive for years, forming a new ridge or furrow each year. It is usually found on the trunk of a living tree.

Aspen Bracket (Phellinus tremulae) in Minnesota infects only quaking aspen and bigtooth aspen. It is the only hoof fungus found on aspen.

Hoof Fungus (Fomes fomentarius) older specimens are lighter and uncracked above. The margin and undersurface are whitish and velvety on actively growing conks. The pores are not stratified. The flesh in cross section does not show white mycelial threads.

Hardwoods, including willow, birch, poplar, alder, apple, ash, black walnut, buckthorn, cherry, hazel, ironwood, maple, and mountain ash.

Year round

Sources

4, 7, 26, 29, 30, 77.

Common

Conks

Pore Surface

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