Guide

Look closerFungi

Birch polypore, the bracket fungus of birch

November to March

The birch polypore is a rounded bracket fungus, whitish to brownish on top, that grows only on birch. Its white to grayish underside and thick rolled rim make it stand out on bare trunks.

Why this time of year

With the leaves down, pale brackets stand out on dead birch trunks and fallen logs. The fruiting bodies are tough and are often still there the next year.

How to notice it

  1. Find a birch tree, standing dead or fallen. Paper birch and yellow birch are both hosts.
  2. Look on dead birch trunks and logs for a semicircular, rounded bracket sticking out from the wood.
  3. Look underneath, without picking it. The underside is white to grayish with tiny pores, and the thick top edge rolls over smoothly into a rim around it.
  4. If the bracket is hoof-shaped, with a hard, woody top banded in gray and no smooth rolled rim, it is likely a different fungus, the hoof fungus, which also grows on birch.

Try this with kids: Can you find a bracket stuck out of a birch like a shelf? Is its edge smooth and rolled, and is its underside white?

Phrase to know: A “bracket fungus” is one that grows out sideways from wood like a shelf.

Safety

  • Look, do not taste. This card gives no advice about eating or using any fungus.
  • Do not climb or lean on dead trees or rotten logs; stay on the path.

Sources

  • mushroomexpert.comMushroomExpert (Kuo): saprobic on deadwood of birch incl. paper and yellow birch; pore surface white aging grayish to brownish; semicircular, convex; thick margin rolled over smoothly to form a rim; annual, but tough fruiting bodies often found the next year.
  • mushroomexpert.comLook-alike: hoof fungus on hardwoods especially birches and beech, brownish pore surface, hoof-shaped, hard woody upper surface with grayish zones.
  • pmc.ncbi.nlm.nih.govPleszczynska et al. 2017 review: 'The host range of the fungus is restricted exclusively to birch species'; brown rot fungus.

Checked against these sources on October 6, 2026.

In the guide for November, December, January, February, March

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