Trametes gibbosa (Pers.) Fr. - Lumpy Bracket

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

Trametes gibbosa - Lumpy Bracket

A saprophytic polypore, the Lumpy Bracket is found on most kinds of hardwood trees but most commonly on Beech, forming brackets on standing timber and more often rosettes on the tops of stumps. It causes white rot.

Often the pale upper surface is discoloured by green algae, the more so in the zones further from the margin. That and the slot-like pores (other whitish Trametes species have round or oval pores) makes this a very easy polypore to identify.

Trametes gibbosa, Lumpy Bracket, on a mossy stump

The splendid display of Lumpy Brackets pictured above was seen in the Forest of Dean, Gloucestershire, England.

Distribution

Fairly common throughout Britain and Ireland, the Lumpy Bracket occurs also in most temperate regions of mainland Europe. This species is also found in parts of Asia. In 2007 Trametes gibbosa was confirmed for the first time in the USA and Canada - an alien introduction, experts believe.

Taxonomic history

Originally described by Christiaan Hendrick Persoon in 1796 at which time it was given the binomial scientific name Merulius gibbosus, the Lumpy Bracket obtained its current scientific name in 1836 when it was described and renamed by the Swedish mycologist Elias Magnus Fries.

Trametes gibbosa, Lumpy Bracket, on a mossy Beech stump

Synonyms of Trametes gibbosa include Merulius gibbosus Pers., Agarico-suber scalptum Paulet, Daedalea virescens (Lázaro Ibiza) Sacc. & Trotter, Daedalea gibbosa (Pers.) Pers., Polyporus gibbosus (Pers.) P. Kumm., Trametes gibbosa f. tenuis Pilát, and Pseudotrametes gibbosa (Pers.) Bondartsev & Singer.

Etymology

Trametes, the genus name, comes from the prefix tram- meaning thin - hence the implication is that fruitbodies of fungi in this genus are thin in section. The specific epithet gibbosa means humped or rounded.

The young pinkish specimens shown on the left are growing on a mossy Beech Stump in the New Forest, Hampshire, England; one of the older common names for this polypore fungus is the Beech Bracket.

Identification guide

Pores of Trametes gibbosa - Lumpy Bracket

Description

White with often a pinkish tinge near to the rim; leathery flesh; typically 5 to 20cm across and roughly semicircular when growing as brackets but more or less circular when growing as a fan on the top of a stump. Brackets vary greatly in thickness but are usually between 1 and 6 cm thick; margins are rounded in young specimens, which are downy on the upper surface, but as fruitbodies age so the upper surface becomes coated with green algae and loses its down, while the margins become more acute.

The tubes are light grey, 3 to 15mm deep and spaced 0.5-1mm apart, terminating in irregular, elongated and maze-like pores (pictured left) that are cream at first and turn ochre with age.

Spores of Trametes gibbosa

Spores

Ellipsoidal to sausage shaped, smooth, 4-6 x 2-2.8µm; hyaline, inamyloid.

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Spore print

White.

Odour/taste

No distinctive smell or taste.

Habitat & Ecological role

This bracket fungus can be seen on many kinds of broadleaf trees, but most commonly on Beech or Sycamore. It is a saprobic fungus and causes white rot.

Season

These perennial bracket fungi sporulate in late summer and autumn.

Similar species

Trametes pubescens, a smaller pale bracket fungus with a velvety or finely hairy upper surface; it usually fruits in overlapping tiers.

Culinary Notes

Although not generally reported as seriously poisonous, these bracket fungi are much too tough to be considered edible. (They may have a cullinary value, however, as substitutes for plates!)

Reference Sources

Fascinated by Fungi, Pat O'Reilly, 2016

BMS List of English Names for Fungi

Kout, J.; Vlasák, J. Trametes gibbosa (Basidiomycetes, Polyporales) in the USA and Canada: Canadian Journal of Botany, Volume 85, Number 3, March 2007, pp. 342-346(5).

Mattheck, C., and Weber, K. Manual of Wood Decays in Trees. Arboricultural Association 2003.

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 and (for basidiomycetes) on Kew's Checklist of the British & Irish Basidiomycota.

Other web pages about this species

Roger Phillips (UK)

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