Major Groups > Polypores > Stemmed, Pale-Fleshed > Bondarzewia berkeleyi


Bondarzewia berkeleyi

[ Basidiomycetes > Russulales > Bondarzewiaceae > Bondarzewia . . . ]

by Michael Kuo

My buddy Bob and I were collecting in Lincoln Trail State Park, in Clark County, Illinois. Bob was merrily filling bags with Cantharellus lateritius, and I was on hands and knees photographing Marasmius siccus when ranger Mike Sanders pulled over--probably to make sure we weren't up to no good, though he was kind enough not to say so. Sometimes I forget what oddballs we must look like to people who don't spend their lives crawling around the woods for mushrooms!

After a brief conversation in which Mr. Sanders must have decided we were more or less harmless, he mentioned a "great big mushroom" he had seen several years in a row. He took us down the road to see it, and our eyes nearly popped out of our heads! Bondarzewia berkeleyi is an amazing polypore that fruits at the bases of hardwoods in eastern North America--amazing not only in its size (one of the clusters we saw was nearly two feet wide!), but also in its spores, which are round and ornamented with spines (see illustration)--like the spores in Russula or Lactarius, and not at all like the smooth, elliptical or cylindrical spores of most polypores. Because of the spores, some taxonomists over the years have suggested there might be a relationship between Bondarzewia and the Russula/Lactarius family. Amazingly, recent genetic research has borne out this proposition; DNA testing has revealed Bondarzewia to belong in the Russulales!

Bondarzewia berkeleyi can be recognized without microscopic examination of spores, however. Distinguishing features include the cream-colored (and non-bruising) fleshy caps, which arise from a gnarled, yellowish brown stem; and the white, non-bruising pore surface, which descends the stem. In the west, it is replaced by Bondarzewia montana, which favors conifers and has a brown cap.


Ecology: Parasitic on hardwoods (especially oaks); causing a white stringy butt rot; also saprobic on the deadwood of hardwoods; growing alone or gregariously at the bases of trees; summer and fall; widely distributed east of the Rocky Mountains. Bondarzewia berkeleyi causes butt rot in the host tree's heartwood. "The wood is first whitened (delignified), and eventually is completely broken down, so that hollow butts result, although before this stage the rot is easily recognized by the persistent medulary rays. These persistent rays interwoven with the stringy remnants have given the name 'string and ray rot' to the decay" (Overholts, 1953; p. 240).

Fruiting Body: 25-80 cm across (!); consisting of one to five caps arising from a single, gnarled stem.

Individual Caps: 6-25 cm across; kidney-shaped or irregular in outline; loosely convex, flat, or with a central depression; dry; velvety or leathery, sometimes radially wrinkled (but never scaly) or with vague, semi-concentric zones of texture or color; whitish to cream colored or pale tan; not bruising.

Pore Surface: Running down the stem; whitish; not bruising, or bruising very faintly brownish; pores angular, 0.5-2 mm across; tubes to 1 cm deep.

Stem: 4-10 cm long; 3-5 cm wide; central or somewhat off-center; yellowish to pale brownish; dry; tough.

Flesh: White; thick; not discoloring or bruising.

Chemical Reactions: Cap surface pale reddish orange with KOH; flesh yellowish with KOH.

Spore Print: White.

Microscopic Features: Spores 7-9 x 6-8 µ; globose to subglobose; amyloid; ornamented with many ridges and spines reaching lengths of 1 µ or longer. Cystidia absent. Hyphal system dimitic.

REFERENCES: (Fries, 1851) Bondartsev & Singer, 1941. (Saccardo, 1888; Overholts, 1953; Smith, Smith & Weber, 1981; Arora, 1986; Gilbertson & Ryvarden, 1986; Phillips, 1991/2005; Lincoff, 1992; Barron, 1999; Roody, 2003; Miller & Miller, 2006; Binion et al., 2008; Kuo & Methven, 2010.) Herb. Kuo 08040305, 06220801.

This site contains no information about the edibility or toxicity of mushrooms.


Bondarzewia berkeleyi

Bondarzewia berkeleyi

Bondarzewia berkeleyi

Bondarzewia berkeleyi

Bondarzewia berkeleyi

Bondarzewia berkeleyi spores

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Kuo, M. (2004, November). Bondarzewia berkeleyi. Retrieved from the MushroomExpert.Com Web site: