Yellow Patches (Amanita flavoconia)

🏷️ Description

Amanita flavoconia—also known as the Yellow Patches, Yellow Wart, Orange Amanita, Yellow-Dust Amanita or the American Yellow Dust Amanita—is one of the most common Amanita species in eastern North America and the Midwest. Appearing from early to mid-summer, this striking mushroom thrives in hardwood and mixed forests, often forming mycorrhizal relationships 🌳 with oaks, pines, and hemlocks.

🛑 Edibility: Toxicity suspected—avoid consumption!

This species can be confused with Amanita frostiana (which has a whiter stem and round, inamyloid spores) and the lesser-known Amanita elongata (more yellow than orange). Its spore print is white, and it has a persistent white annulus near the top of the stalk.

🌎 Distribution: Widespread across eastern North America, Canada, and even Mexico, Amanita flavoconia is frequently found alone or in groups in forests, particularly favoring hemlock and red spruce at high elevations.

🔎 Identification

🍄 Cap

• Size: 1.18 to 3.54 inches (3 to 9 cm)

• Shape: Initially convex, later flattening with age

• Color: Orange to yellow-orange, fading to yellow in sunlight

• Texture: Sticky when wet, smooth under the yellow warts (remnants of the universal veil)

• Margin: Usually smooth but may develop slight striations at maturity

🌿 Gills

• Attachment: Free to narrowly attached to the stem

• Spacing: Close to crowded

• Color: White, sometimes with yellow edges

📏 Stem

• Size: 1.38 to 4.72 inches (3.5 to 12 cm) long, 0.20 to 0.39 inches (0.5 to 1 cm) thick

• Shape: Tapering upwards with a slightly enlarged bulbous base

• Color: Pale yellow to white

• Texture: Bald to slightly roughened

• Ring: Skirt-like and yellowish, high on the stem

• Base: Covered with powdery yellow volval remnants

🍖 Flesh

• Color: White, thin

• Odor: Not distinctive

🧪 Chemical Reactions

• KOH: Negative on the cap surface

⚪ Spore Print: White

🔬 Microscopic Features:

• Spores: 6–9 x 4–6 µm, elliptical, smooth, amyloid

• Pileipellis: A cutis or ixocutis of gelatinized hyphae (3–7 µm wide)

• Basidia: 4-spored, without clamps

• Lamellar trama: Bilateral; subhymenium ramose

🌍 Habitat & Distribution

• Ecology: Mycorrhizal with oaks, birches, and conifers

• Growth Pattern: Found alone, scattered, or gregariously

• Season: July–October (or over winter along the Gulf Coast)

• Regions: Common east of the Rocky Mountains, including Illinois, Indiana, Florida, and Canada

👀 Look-Alikes

• Amanita frostiana: Has round, non-amyloid spores and a more pronounced bulb

• Amanita flavorubescens: Has a yellow cap instead of orange

• Amanita muscaria var. formosa: Larger, with white veil remnants on the cap instead of yellow

📜 Synonyms

• Amanita flavoconia var. flavoconia G.F. Atk. 1902

• Amanita flavoconia var. inquinata Tulloss, Ovrebo & Halling 1992

• Amanita flavoconia var. sinapicolor Tulloss, Ovrebo & Halling 1992

• Amplariella flavoconia (G.F. Atk.) E.-J. Gilbert 1941

• Venenarius flavoconius (G.F. Atk.) Murrill 1948

Photo sources:

Photo 1 - Author: Jimmie Veitch (CC BY 4.0)

Photo 2 - Author: Qadry Anthony (CC BY 4.0)

Photo 3 - Author: Dan MacNeal (CC BY 4.0)

Photo 4 - Author: lisebsb (CC BY 4.0)