bracket fungus

Ganoderma lobatum is a common, wood decaying, bracket fungus. It occurs in North America, Central America, and South America, and there are scattered sightings in Europe, Asia, Africa, the Indian Subcontinent, and Australia. In the United States it occurs east of the Great Plains and in the Pacific Northwest.

The genus Ganoderma is said to be perennial. However, Ganoderma lobatum produces a new fruiting body every year directly beneath the previous year’s growth. For this reason, some sources say that it is annual. Michael Kuo (MushroomExpert.com) says that it is “annual or perennial, lasting for 1–3 years.” Gary Emberger (Fungi Growing on Wood) says that it is annual, but it may appear perennial when the current year’s growth grows up into and fuses with the previous year’s decaying fruiting body.

Ganoderma lobatum is found alone or in groups growing on dead hardwood logs and stumps and sometimes from the wounds of injured living trees. It sometimes grows on and gets its nutrients from dead wood (saprobic). It sometimes grows on living wood, causing a white to straw-colored rot in both the sapwood and the heartwood (parasitic).

The mature cap is woody, semicircular to kidney-shaped, flattened, 4″ to 11¾″ (10 to 30 cm) wide, 3″ to 5½″ (8 to 14 cm) deep, and ⅜″ to 1″ (1 to 2.5 cm) thick. It is grayish red when fresh, becoming brown to grayish brown as it ages. The upper surface is dull, unvarnished, hairless, finely cracked, and wrinkled. It is often concentrically furrowed (zoned). It is hard but thin and crusty. It can be easily punctured with the thumb. The margin on actively growing brackets is white.

The pore surface is whitish to grayish or pale brown when young. When bruised, it instantly discolors to yellowish or grayish brown, eventually turning brown. The entire pore surface turns brown as it ages. There are 4 to 6 tiny, circular pores per 1⁄32″ (1 mm). The tubes are 1⁄64″ to 1⁄16″ (0.5 to 1.5 mm) deep.

The flesh is chestnut brown and cork-like. It is not edible.

There is no stalk.

The spore print is pale brown to dark brown.

Artist’s Conk (Ganoderma applanatum) produces a new layer of tubes on the same conk every year, and the entire conk remains alive.

Deciduous trees

Year-round

Sources

29, 30.

Common

Genus
A recently published molecular phylogenetic analysis of the order Polyporales (Justo et al., 2017) resulted in a revised family-level classification of the order. The revised order moves Ganoderma and other genera formerly placed in the family Ganodermataceae into the family Polyporaceae. As of August 2023, the move has been accepted by IndexFungorum, GBIF, NCBI, and iNaturalist, but not by MycoBank, MycoPortal, or Mushroom Observer.

Ganoderma lobatum
rka54

Amy Stifter
10/1/2024

Location: Medicine Lake Region Trail near 16594 78th Ave N in Maple Grove, Mn.