Artist's Conk

Ganoderma applanatum

Artist's Conk (Ganoderma applanatum) is a flat, woody shelf with a dull brown to gray top, a white rim and a white underside that turns dark brown wherever it's scratched. In the Rocky Mountains it grows mainly at the base of living aspen; Black Hills records are few, on aspen and poplar, and the conks last for years.

Free photos from other sources

Artist's Conk: Flat shelf with a dull brown top, a white rim and a white underside, at ground level among leaves — Ganoderma applanatum. Alan Rockefeller, CC BY 4.0, resized. Get it at the source

Artist's Conk: Broad, pale shelf with a finely cracked top and a thick white rim, at the base of an aspen trunk — Ganoderma applanatum. pinonbistro, CC BY-SA 4.0, resized. Get it at the source

Artist's Conk: Close-up of the white underside: tiny pores and a few dark marks where it was touched — Ganoderma applanatum. Alan Rockefeller, CC BY 4.0, resized. Get it at the source

Artist's Conk: White underside with dark brown marks where it was scratched or bruised — Ganoderma applanatum. Toby, CC BY 4.0, resized. Get it at the source

Artist's Conk: Reddish-brown top with a white growing rim, at the base of a tree in grass — Ganoderma applanatum. John W. Hancock, CC0 1.0. Get it at the source

Quick facts
Family	Polyporaceae · Polypore
Type	Shelf fungus
Season	All year; the conks live for years and add a pore layer each year
Size	Shelf 10–30 cm (4–12 in) wide
Grows on	Base of living aspen; also dead hardwood logs and stumps
Spore print	Brown to orange-brown
Also called	Artist's Bracket, Artist's Fungus
Synonym	Fomes applanatus, Elfvingia applanata, Polyporus applanatus
Eating	This guide doesn't say which mushrooms are safe to eat.

How it lives

A white-rot fungus and root-rot parasite. On aspen it rots the large roots and the base of the trunk, leaving wood mottled with small white and light tan patches that becomes spongy, sometimes with black zone lines. Infected trees usually fall over while still alive, often with healthy-looking crowns, snapping at the roots; the Forest Service ties it to about 90% of windthrow of live aspen in the West. A conk is the only useful sign of infection in a standing tree. Each year the conk adds a new pore layer under the old one, and a 10 by 10 cm (4 by 4 in) patch of pores can release billions of spores in a day.

How do you identify Artist's Conk?

A hard, flat to slightly hoof-shaped shelf with no stem, usually 10–30 cm (4–12 in) wide. The top is dull, not varnished, brown to gray, lumpy and often furrowed in zones. The rim is white and blunt while the conk is growing. The underside is white when fresh, with tiny pores, 4–6 per mm, and turns dark brown at once and for good where you scratch it, which is why people draw on it. The flesh is brown and woody, and the spore print is brown. On aspen it sits at the base of the trunk, usually within about 30 cm (12 in) of the ground. Red-belt Conk usually has a red-orange band and a shiny, resinous top, pale flesh and a cream pore surface, and grows on dead conifers. Tinder Conk is a gray hoof on birch with a brownish pore surface. Aspen Bracket is also on aspen, but higher on the trunk at old branch stubs, with a black, cracked top and a brown pore surface.

When can you find it?

All year; the conks live for years and add a pore layer each year.

Where does it grow?

In the Rocky Mountains it grows mainly on living aspen, at the base of the trunk, and can persist for a while after the tree dies; it also grows on cottonwood and on dead hardwood logs and stumps. Forest Service work found it in almost all aspen stands, more often on moist sites with deep soil. Black Hills records are few: a 1965 Forest Service record, herbarium specimens from Lawrence County (1917, on a poplar) and Crook County, Wyoming (1941, on dead aspen), and 3 research-grade iNaturalist records from 2022 to 2025.