Ganoderma applanatum

Ganoderma applanatum (the artist's bracket, artist's conk, artist's fungus or bear bread) is a bracket fungus with a cosmopolitan distribution. As its common names suggest, it can be used as a drawing medium.

Ganoderma applanatum is parasitic and saprophytic, and grows as a mycelium within the wood of living and dead trees. It grows in single, scattered, or compound formations. It forms fruiting bodies that are 3–30 centimetres (1–12 inches) wide, 5–50 cm (2–19+1⁄2 in) long and 1–10 cm (1⁄2–4 in) thick; exceptionally it may grow up to 75 centimetres (30 in) across. It is hard as leather and woody-textured. The upper surface of the fruiting body appears brown, covered with reddish-brown. The underside is white but stains brown.

The fruiting bodies are perennial, and may persist for multiple years, increasing in size and forming new layers of pores as they grow. These layers can be distinguished in a cross section or from observation of the concentric rings on the upper surface of the fruiting body. This allows the fruiting body's age to be determined using the same method as tree rings.^{[citation needed]}

Brown spores are released from the pores on the underside of the fruiting body. The spores are highly concentrated, and as many as 4.65 billion spores can be dispersed from a 10 cm (4 in) by 10 cm section of the conk within 24 hours. The tubes are 4–12 millimetres (1⁄8–1⁄2 in) deep and terminate in pores that are round with 4–6 per millimetre. The spore print is reddish brown.

The similar Ganoderma brownii has thicker, darker flesh, often a yellow pore surface, and larger spores than G. applanatum. G. oregonense, G. lucidum, and Fomitopsis pinicola are also similar. Fomes fasciatus produces a white spore print.

G. applanatum is a wood-decay fungus, causing a rot of heartwood in a variety of trees. It can also grow as a pathogen of live sapwood, particularly on older trees that are sufficiently wet. It is a common cause of decay and death of beech and poplar, and less often of several other tree genera, including alder, apple, elm, buckeye and horse chestnut, maple, oak, live oak, walnut, willow, western hemlock, Douglas fir, old or sick olive tree, and spruce. G. applanatum grows more often on dead trees than living ones.

There are anecdotal references of higher primates consuming this fungus for self-medication. In her book Gorillas in the Mist (1983), Dian Fossey wrote:

Still another special food (for the gorillas) is bracket fungus (Ganoderma applanatum)... The shelflike projection is difficult to break free, so younger animals often have to wrap their arms and legs awkwardly around a trunk and content themselves by only gnawing at the delicacy. Older animals who succeed in breaking the fungus loose have been observed carrying it several hundred feet from its source, all the while guarding it possessively from more dominant individuals' attempts to take it away. Both the scarcity of the fungus and the gorillas' liking of it cause many intragroup squabbles, a number of which are settled by the silverback, who simply takes the item of contention for himself.