Mossy Maze Polypore

Conservation Status

IUCN Red List

not listed

NatureServe

NNR - Unranked

Minnesota

not listed

Description

Mossy Maze Polypore is a widespread and very common bracket fungi (polypore). It occurs in Europe and Asia, and throughout North and Central America. In the United States it is common east of the Great Plains, uncommon in the Pacific northwest, and absent elsewhere. In Minnesota it is very common in the eastern half of the state, uncommon to absent in the western half. It is found year round in deciduous and mixed forests. It grows in overlapping clusters on dead hardwood stumps and logs. It is saprobic, obtaining its nutrients from rotting wood. It causes white rot in wood.

When growing on the underside of a log it looks like a pore surface that has lost its cap. When on the top or side of a log or stump it produces a semi-circular, kidney-shaped to fan-shaped, shelf-like or bracket-like cap. The cap is 1¼″ to 4″ (3 to 10 cm) wide. It is attached to the substrate without a stalk. The upper surface is whitish to brownish or dark brown, but is often green due to a covering of algae. It is concentrically zoned and has a broad pale margin. It is densely covered with fine hairs, sometimes velvety. It is smooth at first, becoming wrinkled or bumpy with age.

The pore surface is whitish when young, becoming smoky gray at maturity. The pores are slotted, maze-like. The tubes are up to ⅛″ (4 mm) deep. They often break into teeth as they age.

When sliced, there is a thin dark line just beneath the upper surface. The flesh is whitish, leathery, and tough. It is inedible.

The spore print is white.

Similar Species

Thin-Walled Maze Polypore (Daedaleopsis confragosa) upper surface is hairless or slightly hairy. The pore walls are relatively thin and white to tan or brown.

Habitat and Hosts

Dead hardwood stumps and logs in deciduous and mixed forests

Ecology

Season

Year round

Distribution

Sources

7, 24, 30, 77, 83.

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu. Accessed 9/30/2026).

Cerrena unicolor (Bull.) Murrill in Bánki, O., Roskov, Y., Döring, M., Ower, G., Hernández Robles, D. R., Plata Corredor, C. A., Stjernegaard Jeppesen, T., Örn, A., Pape, T., Hobern, D., Garnett, S., Little, H., DeWalt, R. E., Miller, J., Orrell, T., Aalbu, R., Abbott, J., Abreu, C., Acero P, A., et al. (2026). Catalogue of Life (2026-08-26 XR). Catalogue of Life Foundation, Amsterdam, Netherlands. https://doi.org/10.48580/dgyy9

Mycology Collections Portal (MyCoPortal) https://www.mycoportal.org/portal/collections/index.php). Accessed 9/30/2026.