Black-staining Polypore
(Meripilus sumstinei)
Immature Berkeley's Polypore, sculpture

Black-staining Polypore, side view

What makes this polypore special and distinct is that its whitish flesh stains dark black when bruised or when it ages.

The clustered, sharp-edged, fan- to spoon-shaped caps are 2-8 inches across. Whitish, greyish, to dull yellow, they begin to blacken minutes after being handled, or as the mushroom ages, beginning at the edges.

Black-staining Polypore From Below

Black-staining Polypore from below

Note the white flesh turning black.

The pores are too tiny to see without magnification, distinguishing it from the similar-looking Berkeley's polypore, which has large pores, even before it begins to blacken.
Hen-of-the-woods, which has smaller, spoon-shaped caps, also doesn't blacken.
Black-staining Polypore Pores

Black-staining Polypore

Note the pores visible only under magnification

The spore print is white.

There's not much of a stalk, and it's the same color as the rest of the mushroom.

You usually find a few pounds of this mushroom, but bunches may weigh as much as 30 lbs!

Black-staining Polypore Detail

Young Black-staining Polypore, Detail

It grows singly or in groups near the base of stumps or trees, especially oaks, from fairly early in the summer until late fall, throughout the eastern half of North America. It often comes up in the same places year after year.

Black-staining Polypore Caps

Young Black-staining Polypore Caps, detail

Reputed to taste like liver, I find it to taste like steak, with a similar texture, especially seasoned with flavorings traditionally used with steak.

Unfortunately, you need to find the mushroom when it's very young, before it becomes leathery. I usually find it when only the edges are tender enough to pinch through (and eat), so I've only had a few opportunities to experiment with this very tasty, chewy mushroom.

I like to sauté it in oil with herbs and spices 5-10 minutes, then add a liquid or sauce and simmer it another 20 minutes to tenderize it. I'd like to try pressure cooking the mushroom in a soup.