Artist's Conk

Description

Ganoderma adspersum, commonly known as the Artist's Conk, is a large, perennial, woody polypore fungus belonging to the genus Ganoderma. It is characterized by its dull to somewhat shiny, often lumpy or radially furrowed upper surface and a distinct, creamy white pore surface that darkens instantly when bruised or 'drawn' upon. This species is saprobic and parasitic, primarily found growing on the base of living deciduous trees, or on dead stumps and logs. Its robust nature allows it to persist for many years, adding new layers of growth annually, forming a large, hoof-shaped conk.

How to Identify

Cap

The upper surface (pileus) is dull to somewhat shiny, often lacking a prominent 'varnished' appearance compared to other Ganoderma species (though some regional variations can show some varnish). The color ranges from gray-brown to dark gray or blackish, often with concentric growth zones (zonate) and radial furrows or lumps. The margin (edge) is typically thick, rounded, and often lighter in color, usually whitish to yellowish-brown, especially in actively growing areas. It can be quite lumpy and irregular.

Gills

Ganoderma adspersum, being a polypore, does not have gills but rather a pore surface. The pore surface is creamy white to buff, becoming grayish or brownish with age. It is remarkable for instantly bruising dark brown or black when touched or scratched, making it a popular medium for 'drawing' by artists. The pores are very minute, 4-6 per millimeter, with thin dissepiments (walls between pores). The tube layer (below the pore surface) is brown, layering indistinctly in older specimens, up to 1-2 cm thick.

Stem

This species is sessile, meaning it lacks a true stem (stipe). It grows directly attached to the host substrate.

Flesh

The flesh is very tough, corky to woody, and fibrous. It is uniformly brown, often a reddish-brown or cinnamon-brown color, without significant marbling or changes in color upon exposure to air.

Fruiting body

The fruiting body is a large, perennial, sessile (lacking a stalk) bracket fungus, typically hoof-shaped to ungulate or triquetrous (triangular in cross-section). It grows directly out from the host tree or wood. The entire fruiting body can range from 10 to 60 cm (4 to 24 inches) across and often extends outward 5 to 20 cm (2 to 8 inches) from the substrate, with a thickness of 5 to 15 cm (2 to 6 inches) at the point of attachment. Younger specimens may be lighter in color, becoming darker and woodier with age. The weighty nature is notable.

Habitat

Typically found solitary or in small groups, growing saprobically on dead logs, stumps, or fallen branches of deciduous trees, and also as a parasite on the base of living deciduous trees, causing a white rot. Favored hosts include oak, beech, maple, and other hardwoods. Less commonly found on conifers.

Key Facts

• Cap surfaces: Dull to somewhat shiny, often lumpy or radially furrowed, gray-brown to blackish, margin often whitish/yellowish.
• Growth Form: Sessile, solitary or in small overlapping groups.
• Spore Print: Brown to reddish-brown.
• Body color: Upper surface dull gray to blackish-brown; pore surface creamy white, bruising dark brown/black; flesh brown.
• Odor: Mild, indistinct.
• Flesh bruises: Not applicable to flesh; pore surface bruises instantly dark brown/black.
• Height: Not applicable (sessile); thickness up to 15 cm (6 inches).
• Cap Diameter: 10-60 cm (4-24 inches) across.
• Nutrient gathering: Saprobic (on dead wood) and parasitic (on living trees), causing white rot.

Quick Check

• Odor: Mild, faintly fungoid to somewhat reminiscent of licorice, not distinctive.
• Fruiting: Perennial, hoof-shaped to ungulate bracket, growing directly on wood.
• Substrate: Deciduous trees (living or dead), rarely conifers.

Where to Find

Finding Tips

Similar Species

Scientific Classification

Phylum

Basidiomycota

Class

Agaricomycetes

Order

Polyporales

Family

Ganodermataceae

Genus

Ganoderma

Storage Information

• Max Temperature: N/A
• Freezing duration: N/A
• Min Temperature: N/A
• Refrigeration: N/A

How to Clean

Artist's Conk is not typically cleaned for culinary purposes as it is inedible. If collected for artistic purposes, a dry brush can be used to remove loose debris. Avoid wetting the pore surface if you intend to draw on it.

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