Gymnopilus junonius, known as the Spectacular Rustgill, is a large, vividly colored mushroom recognized for its brilliant orange to yellow cap, rust-colored gills, and bitter taste. Though sometimes mistaken for edible species due to its size and color, it is not recommended for consumption due to its bitter flavor and potential psychoactive compounds. It grows in large clusters on decaying wood and is one of the most visually striking wood-inhabiting fungi.

Native to temperate regions across North America, Europe, Asia, and Australia, this species has been extensively studied due to its occasional presence of psilocybin and other bioactive compounds. However, its toxicity and variability in chemistry make it unreliable and unsafe for recreational or culinary use. Historically, it was more often a subject of mycological curiosity than food or medicine.

It is often used as a visual indicator of forest health, showing where decay and wood turnover are occurring.

This mushroom forms dense, overlapping clusters on stumps and logs of hardwoods, especially in autumn. Caps range from bright yellow to deep orange, with a fibrous surface and gills that stain rust-brown as spores mature. The spore print is rusty-orange, and the flesh has a distinctively bitter taste, even when cooked.

Although some varieties contain trace levels of psilocybin, it is not considered a reliable or safe psychoactive mushroom and should be appreciated for its aesthetic and ecological role rather than ingestion.

Physical Characteristics

Caps:

Bright orange to yellow, often with a rusty brown center, up to 30 cm across, convex with an inrolled margin when young, becoming flatter with age.

Gills:

Yellow to rusty orange, close, adnate to adnexed.