Ganoderma resinaceum Boud.

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

Ganoderma resinaceum

Ganoderma resinaceum is a rare poroid fungus that persists throughout the year. The yellow resin from the edges of this large bracket hardens rapidly. As the fruiting body ages, this beautiful fungus turns black and can then be mistaken for the Hoof Fungus, Fomes fomentarius.

When this tough bracket is broken or cut, a thick yellow resin oozes from the fungus and rapidly sets to form a hard shiny surface; the specific name reflects this characteristic.

Ganoderma resinaceum, closeup of cap surface

The huge bracket pictured above is attached to the basal roots of an old oak tree in the New Forest, Hampshire, England. At first glance it looks much more like a Giant Polypore Meripilus giganteus than a Ganoderma, and I almost passed it by on the basis that impressive Giant Polypores are so common that they hardly create an impression any more!

What gives this imposter away, however, is the fact that the grass and other vegetation all around the bracket fungus is tinted brown by spores, and Meripilus spores are white. not brown. (The upper surfaces of Ganoderma resinaceum are also much tougher than those of the relatively short-lived Giant Polypore.)

Distribution

A rare find in Britain and Ireland, Ganoderma resinaceum is more common in some northern and central parts of mainland Europe.

This impressive fungus has a very wide distribution: it has been reported from northern Africa, Asia, Australia and both South and North America.

Ganoderma resinaceum, young brackets photographed by David Kelly

Taxonomic history

The bracket fungus was described in 1889 by the French mycologist Jean Louis Emile Boudier (1828 - 1920), who gave it what remains its currently-accepted scientific name, Ganoderma resinaceum .

Synonyms of Ganoderma resinaceum include Fomes resinaceus (Boud.) Sacc.

Etymology

Ganoderma comes from the Greek words Ganos and derma and translates to 'shining skin'. Compared with many other members of this genus, Ganoderma resinaceum is quite bright and shiny... provided you wash off any spore dust from the upper surface of the cap. The specific epithet resinaceum means 'resinous' and is a reference to the hard-setting sticky liquid that emanates from fruitbodies that are damaged.

Identification guide

Spore-covered cap of Ganoderma resinaceum

Cap

A startling sight when young a not covered in its reddish-brown spore dust, this fungus sometimes forms tiers of brackets which occasionally merge. Individual brackets are 15 to 35cm across and 4 to 8cm thick when fully grown. The cap of the fruiting body has a light yellowish margin and a beautiful orange-tinged rufous brown top.

Tubes of Ganoderma resinaceum

Tubes

The brown tubes are 8 to 20mm deep, and they terminate in roundish pores.

Pores of Ganoderma resinaceum

Pores

Spaced at 3 to 4 per mm, the pores are initially whitish or more often very pale yellow when the fruiting body is young, turning light brown with age or when bruised.

Spores of Ganoderma resinaceum

Spores

Ellipsoidal to ovoid, truncate at one end, smooth; 9-11 x 5-7µm.

Spore print

Reddish-brown.

Odour/taste

Spicy odour and a bitter taste.

Habitat & Ecological role

Parasitic on living broadleaf tree trunks, particularly oaks and Beech.

Season

Visible throughout the year but releasing spores in summer and autumn.

Similar species

Ganoderma lucidum usually has a lateral stem it has smaller spores and larger pores.

Ganoderma applanatum, the Artist's Fungus, is ochre brown with a much thinner white margin than Ganoderma resinaceum.

Ganoderma resinaceum, southern Portugal

Culinary Notes

These bracket fungi are far too tough to be edible, and in any case they are rare in Britain and Ireland and therefore should not be collected for any reason other than serious scientific research.

The huge bracket shown above was growing on an oak tree in the Algarve region of southern Portugal. The specimen seen below was growing at the base of a dead Silver Maple tree in Burleson, TX USA, and the picture is shown by courtesy of Deby Feeley.

Ganoderma resinaceum, USA

Reference Sources

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

Pat O'Reilly, Fascinated by Fungi, 2016.

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.

Acknowledgement

This page includes a picture kindly contributed by David Kelly.

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