Lenzites betulinus  (L.) Fr. - Birch Mazegill

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Polyporales - Family: Polyporaceae

Distribution - Taxonomic History - Etymology - Identification - Culinary Notes - Reference Sources

From the top this attractive bracket is easily misidentified. There are so many colour variations in Trametes versicolor that it is almost forgivable to assume that any fan-shaped thin bracket with concentric, many-zoned bands on its upper surface must be yet another Turkeytail. No so! Just as variable in colour as Trametes versicolor is this thin and leathery fan-like bracket, again with many concentric colour bands, but there is one very important feature distinguishing it from Turkeytail... it has gills.

To spot the difference between Lenzites and Trametes, you have to look on the underside of a bracket. Lenzites betulinus has definite gill-like slots rather than pores. They aren’t merely very long mazegill slots either, but structures very similar to the gills of an agaric mushroom. The Birch Mazegill is, nevertheless, a polypore – taxonomically, that is!

Distribution

An uncommon but conspicuous bracket fungus, the Birch Mazegill is found occasionally throughout Britain and Ireland.

Taxonomic history

In 1753, when Carl Linnaeus described this bracket fungus, he gave it the binomial scientific name Agaricus betulinus. The great Swedish mycologist Elias Magnus Fries transferred this species to the genus Lenzites in 1838, and Lenzites betulinus is still generally-accepted scientific name today.

Lenzites betulinus has several synonyms including Agaricus betulinus L., Agaricus flaccidus Bull., Daedalea variegata Fr., Apus coriaceus Gray, Daedalea betulina (L.) Fr., Lenzites flaccida (Bull.) Fr., and Lenzites variegata (Fr.) Fr.

Etymology

Lenzites, the genus name, was established in 1835 by Elias Magnus Fries, perhaps honouring German mycologist Harald Othmar Lenz (1798 - 1870). The specific epithet betulinus means 'of birch trees' - a reference to the genus of host trees upon which this bracket fungus is most commonly found.

Identification guide

	Cap Many-zoned when mature, often pinkish fan-like brackets, up to 10 cm across and 1 to 2 cm thick at the point of attachment; usually in tiers.
	Gills The gills are white at first, turning brown with age; well-spaced or fairly close; sharp-edged; tough; up to 1 cm deep.
	Spores Cylindrical, smooth, 5-6 x 2-3µm; inamyloid. Spore print White.
Odour/taste	Not distinctive
Habitat & Ecological role	On living or dead hardwood trees, particularly birch.
Season	All through the year, but shedding spores in autumn.
Similar species	Trametes versicolor, Turkeytail, has pores rather than gills.

Culinary Notes

The Birch Mazegill is tough and inedible.

Reference Sources

Fascinated by Fungi, 2nd Edition, Pat O'Reilly 2016, reprinted by Coch-y-bonddu Books in 2022.

Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers; CABI, 2008

Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi.

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