Gilled Polypore

Birch Mazegill, Multicolor Gill Polypore
Trametes betulina

This shelf-like, fan-shaped mushroom, found on dead hardwood, is notable for its hairy, concentric bands and its unusual true gills on the underside.

Appearance

• Shelf-like to fan-shaped (2-10 cm. wide)
• Without a stipe (stem)
• Upper surface is hairy, with concentric bands of cream, pale-buff, yellow-brown, or grayish-brown
• Lower surface has white true gills
• Spore print white
• Grows scattered to clustered in overlapping shelves

ID Tips

• Can be confused with turkey-tail (T. versicolor) and conifer mazegill (Gloeophyllum sepiarium)
  • Gilled polypore
    • Upper surface is cream, pale-buff, dingy yellow-brown, or grayish-brown
    • Lower surface has white true gills
    • Grows on dead hardwood (e.g. oaks)
  • Turkey-tail
    • Upper surface is gray, brown, or cream
    • Lower surface has pores
    • Grows on dead hardwood (e.g. oaks)
  • Conifer mazegill
    • Upper surface is rusty-brown
    • Lower surface has brown true gills, often mixed with elongate pores
    • Grows on dead conifers

At Edgewood

• See iNaturalist for observations in Edgewood

About

• Basidiomycetes – a major lineage of fungi that usually produce spores within basidia (club-like structures)
• Found from early to late winter
• Saprotrophic – grows on dead hardwood (e.g. oaks), occasionally on conifers
• Edibility (San Mateo County Parks prohibits removal of any natural material)
  • Inedible; too tough
  • Unless you are an expert, do not pick and consume wild mushrooms

Fun Facts

• Gilled polypore belongs to the Polypore family of fungi (Polyporaceae), whose members usually have vertical pores on the underside of their caps
  • As nature always has exceptions, this species has true gills instead!
• The Polypore family of fungi (Polyporaceae) are typically saprotrophic
  • Identifying the tree they are growing on can help determine the specific species

Learn More

Kuo, M. Oct. 2022. The polypores. MushroomExpert.Com

Roehl, T. 2017, Jul. 14. #013: Characteristics of division Basidiomycota. Fungus Fact List. Fungus Fact Friday.

Roehl, T. 2017, Jul. 7. #030: Mushroom morphology: Polypores. Fungus Fact List. Fungus Fact Friday.

References

Desjardin, D.E., M.G. Wood, and F.A. Stevens. 2016. California Mushrooms: The Comprehensive Identification Guide. Timber Press, Portland, Oregon.

Kuo, M. 2007, Mar. 4. Lenzites betulinus. MushroomExpert.Com.

Wood, M., and F. Stevens. 2024. Trametes betulina. The Fungi of California. MykoWeb.