Polypore Mushrooms: Brackets, Host Trees and Products

What the underside and the host tree show

Most members grow as brackets, shelves or conks on wood, and the pore surface underneath often tells you more than the top. Turkey tail shows why. Several unrelated fungi share its banded fan, and the white pore surface underneath is what makes it turkey tail.

The host tree does much of the first sorting. Birch polypore grows only on birch, and agarikon grows on old conifers, especially larch. Knowing the host shortens your list of candidates before you look at any pore.

Why is the danger lower here, and where does it move?

Few polypores have a deadly lookalike. Maitake returns to the base of the same oak year after year, and its closest confusions are other large polypores. Even with that low risk, you check a hard lacquered shelf such as reishi against its profile before any use.

Chicken of the woods carries the group's main eating caution, because several species share its bright orange shelf and people do not tolerate them equally well. Four habits cover almost every reported problem. You avoid conifer and eucalyptus hosts, skip old chalky specimens, cook it thoroughly and start with a small portion.

Most of the other members are so woody or bitter that people use them as teas, powders and extracts and leave them out of meals.

Medicinal polypores and the products made from them

For the medicinal members, most documented harm comes from concentrated products and little from picking. Published case reports describe liver injury after Ganoderma powder, including one fatal case. In the two earliest reports, the patients had used traditionally boiled reishi without harm before switching to powder. Chaga carries the highest measured oxalate load of any commonly sold fungus, and two published cases describe kidney damage from sustained use.

Product labels do not always name one species. The name Mesima also turns up on closely related Sanghuangporus fungi. Antler reishi is a growth form and not a species, and its material may belong to more than one Ganoderma species.

Where do people misread the polypore label?

Two members reach buyers in forms that look nothing like a bracket. Chaga is the black cracked mass on a living birch, and that mass is sterile tissue and not a fruiting body. People most often mistake a burl for it, and a burl is the tree's own wood, wrapped in bark as an unbroken skin.

Poria comes to market as a sclerotium, a buried storage structure with no shelf at all. Roots, woody burls, plant tubers and the sclerotia of other fungi can all pass for a buried brown lump with a pale interior.

Photographs are weak evidence for the dark perennial brackets, which converge on the same rough shelf or hoof shape. Even the red band of red-belted conk does not identify that species, because DNA studies have split it into several regional species.