Home / Species Database / Black-staining Polypore

How to Identify Black-staining Polypore

Meripilus sumstinei
EDIBLE* Season // Jul-Oct Family // Unknown

Description

Large compound rosette 8-24+ inches wide composed of many overlapping fan-shaped caps 2-6 inches wide arising from central base. Pale tan to brown caps that BLACKEN when bruised or with age - diagnostic feature. White to cream pore surface that also blackens. Soft and spongy texture. Can weigh 10-30+ pounds. Distinctive black staining.

Specimen Profile

FamilyUnknown
GenusMeripilus
EdibilityEdible*
Toxicityunknown
SeasonJul-Oct
HabitatSaprobic and parasitic at bases of living and dead hardwood trees, particularly oak, maple, beech, and elm. Causes white rot of roots and lower trunk. Forms large rosettes at tree bases, stumps, and buried roots. Common in mature hardwood forests and urban settings.
RegionEastern North America, Midwest, Southeastern United States, Great Lakes region, Pacific Northwest, Widespread across North America

Habitat & Distribution

Habitat: Saprobic and parasitic at bases of living and dead hardwood trees, particularly oak, maple, beech, and elm. Causes white rot of roots and lower trunk. Forms large rosettes at tree bases, stumps, and buried roots. Common in mature hardwood forests and urban settings.

Region: Eastern North America, Midwest, Southeastern United States, Great Lakes region, Pacific Northwest, Widespread across North America

Seasonality

Late summer through fall, typically July-October. Peak fruiting in August-September. Can flush multiple times per season. Most abundant in late summer. Often in same location annually.

Typical months: Jul-Oct

Common Lookalikes

Always verify identification to avoid these similar species. The differentiator is the point — learn the one or two tells that separate them:

Grifola frondosa (gray-brown, doesn't blacken, different cap arrangement)

Bondarzewia berkeleyi (lighter, larger caps, doesn't blacken quickly)

Other large polypore rosettes (don't blacken when handled)

Polyporus umbellatus (smaller, different structure)

BROWSE ALL SPECIES →

Track your Black-staining Polypore finds

Pin the patch before you leave it. Coordinates, photos, and field notes stay on your device — and the offline lookalike guide travels with you into the deep woods.

Download Mushroom Tracker

Disclaimer: This guide is for educational purposes only. Never consume a wild mushroom unless you are 100% certain of its identification.