I have found *Polyporus frondosus fungus growing at the base of a red oak (Quercus rubra) the suffered signicant root loss 4-5 years ago during construction. This is a fleshy, multi-capped (layered) fungus, light to dark brown caps, white flesh and spore print.

I haven't been able to find much in the literature or on the web, other that it is used in nutriceuticals and is edible (choice!). The one reference I have found, and quoted on the web is from Mushrooms of North America, Orson Miller, 4th printing 1980. It only says it grows near, but not on, the base of oaks. I need to know if this is a pathogen or parasite, or a decay fungus.

TIA
Russ

Reply to post by Russ Carlson, on October 18, 1999 at 16:10:24:

Russ, are you sure it's not P dryadeus?

Reply to post by Russ Carlson, on October 18, 1999 at 16:10:24:

From
"One Thousand American Fungi" McIlvaine & Macadam, Dover Publications, 1973.

Speaking of Polyporus in general, p.396

"They are the ever active pruners of our trees and converters of forest debris."

I would make a tentative inference that it *might* be a decomposer.

Polyporus frondosus specifically:

According to Curtis was sold for food in the Roman market. Rare, found on roots, stumps, etc. Found in N. Carolina, Iowa, New York, West Virginia, Chester Co. PA.

"Good flavor when young. Older it makes a well flavored gravy, or is edible if chopped fine and very well cooked."

(Personally, I would recommend lots of onion, scallions, celery and carrots with it).


There is a lengthy description and photo if you need to cross check the ID. Not much more help than that. Sorry.

Reply to post by Reed Holt, on October 18, 1999 at 16:10:24:

Actually, not 100% sure of ID. In two references I have, it keys out to P. frondosus, and several images I have found appear very close.

Can you suggest how to distinguish them? Characteristics of P. dryadeus?

Reply to post by Paul M Davis, on October 18, 1999 at 16:10:24:

This is northern New Castle County, DE, which is probably less than 10 miles from Chester Co.

Edibility- supposedly a choice mushroom, when young. The ones I found were getting old and tough.

Other sources have told me it is a saprophyte and weak parasite, causing a white butt rot. Obviously not good, since this oak is about 36" diameter, leans over two houses, and has numerous basidocarps on all sides at the base.

The tree suffered severe construction damage 5 years ago- cut, fill, compaction, etc.

Reply to post by Russ Carlson, on October 18, 1999 at 16:10:24:

JS Boyce, 1948; Forest Pathology p. 392.
Causes a butt rot of the heartwood of living oaks and chestnut.
Decay is usually connected with fire scars (today it would be construction scars).
Annual sporophores come from decayed roots. Or appear at base of tree.
I would worry. Peter

Reply to post by Russ Carlson, on October 19, 1999 at 13:18:55:

I'm sorry Russ, I've been busy on a cancer case
day/night for 2 weeks. I haven't checked the posts.
In the oaks, a white mottled rot usually begins in the roots developing later in the heartwood at the ground level. It generally doesn't not spread appreciably above that. The basidiocarps are light brown almost yellow, turning darker until maturity, drying to become gray and "crackled". The interior is reddish-brown. The area below and under these carps, the soil, the mycelial growth will enter and grow down several inches and 'bind' the soil into a hard mass. This will reproduce also. If you have multiple basidiocarps, the decay is massive at a critical area of structural need.
I look for the distinctive 'honey' color.
In P frondous, here, on the oaks, the basidiocarp is a distinctive white...wait...cancer call. i have to go tomy etc

Reply to post by Reed Holt, on October 19, 1999 at 22:51:36:

These basidiocarps were a darker color when I found them, still actively growing. Not tan, almost a light chocolate brown. After 3 days on my desk, they had turned white from prolific spore release (white spore print). The color was still darker underneath.

I also found a reference in USDA Agri Handbook 386, Diseases of Forest and Shade Trees of the US. Indicates moderate growth rate, primarily a root disease (not going up the stem much).

All indications are that the tree is at risk of basal failure.