Ganoderma resinaceum Boud.

A mature bracket at the base of a roadside oak in Basildon, Essex
A senescent bracket with dulled purplish colourations in Buckhurst Hill, Essex
An extensive deck of maturing brackets on oak near Windsor Great Park, Surrey
An emerging bracket beneath a broken-off bracket from a prior year in Maidstone, Kent
A flesh cross-section from a bracket on beech near Hampstead Heath, London

A mature bracket at the base of a roadside oak in Basildon, Essex
A senescent bracket with dulled purplish colourations in Buckhurst Hill, Essex
An extensive deck of maturing brackets on oak near Windsor Great Park, Surrey
An emerging bracket beneath a broken-off bracket from a prior year in Maidstone, Kent
A flesh cross-section from a bracket on beech near Hampstead Heath, London
Developing fruit body on oak in Kent, UK.
Mature slightly aberrant brackets on a fallen oak in Basildon, UK.
Very young fruit bodies emerging on oak in Birmingham, UK.
Developing fruit bodies on oak in London, UK.
Tier of developing brackets on oak in Reigate, UK.

Common name

Lacquered bracket

Often found on

Oak.

Sometimes found on

Beech, hawthorn, hornbeam, lime, maple, plane, poplar, willow.

Location

Typically restricted to the base of the tree and out on buttress roots. Tends to fruit in the same / a proximal location each year. Found more routinely in warmer areas of England (south).

Description

Annual . Tough and slightly rubbery. Upper surface often varnished (photo a). Begins as a golden-yellow to white mass. Often rimmed golden-yellow to white. Pore layer white. Spore brown. Flesh a chocolate-coffee brown. Rubbery. Very hard to cleanly slice with a blade.

Confused with

Fomitopsis pinicola (white flesh); Ganoderma australe; Ganoderma lucidum (usually smaller and more reddish / often stalked).

Significance

Attributed to a selective white rot of wood. Can cause basal cavity formation. Prompts buttress development. Parasitic . Considered more aggressive on American oaks and Turkey oak. Decay can be subterranean. Where a tree lacks buttressing, investigations into structural stability are more acutely necessary. Where targets exist, investigations into structural stability and stem hollowness are recommended.