Gymnopilus luteus

🏷️ Description

Meet the Gymnopilus luteus, also known as the yellow gymnopilus! 💛 This vibrant mushroom is a proud member of the Gymnopilus junonius family but stands out with its sunny yellow hues and slender stem. Unlike its cousins, it sticks to the hardwood forests of eastern North America, thriving on damp, rotting wood from June to November. 🍂🌦️

With its medium to large cap, orange-brown spore print, and a partial veil that leaves a ring on its stem, this fungi is easy to spot—but be careful! ⚠️ Its bitter taste and psychoactive properties (thanks to psilocybin and psilocin) make it inedible. 🌈💫

👀 Often confused with look-alikes like Gymnopilus junonius or G. speciosissimus, G. luteus is a solitary or gregarious grower, popping up in small clusters on decaying hardwood. 🪵🍃

🔎 Identification

🍄 Cap:

1.18 to 7.87 inches (3 to 20 cm) wide, starting convex-hemispherical, expanding to broadly convex or nearly flat with age. The margin is often irregularly infolded, slightly overhanging the gills. Its color ranges from buff yellow to warm buff orange, sometimes darker at the center. The surface is dry, smooth, silky, or finely floccose-fibrillose, occasionally sporting small scales. The firm, pale yellow flesh stains orange-brown or bluish-green when injured or with age.

🍃 Gills:

Adnexed, thin, and closely spaced. They begin pale yellow and darken to rusty brown as the mushroom matures.

🟤 Spore Print:

Rusty brown to orange-brown — a key identification feature!

🌾 Stem:

1.57 to 3.94 inches (4 to 10 cm) long and 0.20 to 1.18 inches (0.5 to 3 cm) thick, firm and solid, often equal or slightly swollen at the base. It mirrors the cap's color and develops yellowish-rusty stains when handled. The surface is finely hairy, with a fragile ring or ring zone near the top. Like the cap, it can bruise orange-brown or bluish-green.

👃 Odor & 👅 Taste:

The gills emit a strong anise-like aroma, helping to distinguish it from similar species. However, its very bitter taste makes it inedible.

🧪 Microscopic Features:

• Spores: 6–9 × 4.5–5.5 µm, elliptical, minutely warty, dextrinoid, and without a germ pore.

• Cheilocystidia: Mostly lageniform to lecythiform, sometimes capitate.

• Pleurocystidia: Infrequent or absent.

• Caulocystidia: Abundant above the ring zone, often hair-like.

• Clamp Connections: Present.

✨ Special Traits:

• Bruising: Light blue or green bruising may occur, especially on younger pins, but it's slower than in Psilocybe species.

• Chemical Reaction: KOH applied to the cap turns it red.

• Potency: Contains low levels of psilocybin and psilocin (~0.1–0.5% total tryptamines when dried), contributing to its hallucinogenic properties.

🏞️ Habitat & Season:

A saprobic species found on dead hardwoods (and sometimes conifers), growing solitary, gregariously, or in small clusters. It thrives from June to November across the eastern United States and Canada, favoring damp, well-rotted wood.

Photo sources: Annie Weissman (Public Domain)