Polyporus umbellatus

[ Basidiomycetes > Polyporales > Polyporaceae > Polyporus . . . ]

by Michael Kuo

Polyporus umbellatus fruits from the ground, near the bases and roots of hardwoods across northern North America. It is apparently fairly rare, and is encountered far less frequently than the somewhat similar Grifola frondosa. The fruiting body consists of many small, smoky brown, roundish caps (as opposed to the larger, fan-shaped and irregular caps of Grifola frondosa); the undersurfaces are white; and the individual branches are discrete immediately below the caps but become fused together into one solid structure below.

Description:

Ecology: Saprobic or parasitic on the roots and wood of hardwoods; causing a white rot; fruiting at the bases of trees; often reappearing in the same place in subsequent years; summer and fall; rare but fairly widely distributed in northern North America, southwards to Tennessee and Kansas.

Fruiting Body: 30-50 cm across or more; composed of multiple caps atop discrete stems that fuse into a large stem structure.

Caps: 1-4 cm across; more or less circular; pale smoky brown or whitish; often becoming finely scaly.

Pore surface: White; running down the stems; with 1-3 angular pores per mm; tubes to 2 mm deep.

Stem: White; irregular; central to the caps; fusing into one or more larger structures; arising from an underground knot of tissue.

Flesh: Firm; white.

Odor and Taste: Mild.

Spore Print: White.

Microscopic Features: Spores 7.5-10 x 3-4 µ; smooth; cylindric; inamyloid. Cystidia absent. Hyphal system dimitic. Clamp connections present.

REFERENCES: (Persoon, 1801) Fries, 1821. (Saccardo, 1888; Overholts, 1953; Smith, Smith & Weber, 1981; Gilbertson & Ryvarden, 1987; Lincoff, 1992; Barron, 1999; Roody, 2003; Kuo, 2007.) Herb. Kuo 09190301.

Grifola umbellata is a synonym.

Further Online Information:

Grifola umbellata at Roger's Mushrooms

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Cite this page as:

Kuo, M. (2010, March). Polyporus umbellatus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/polyporus_umbellatus.html