Agaricus trisulphuratus

🏷️ Description

With its vibrant cap, crowded gills, and striking yellow scales, the Scaly Tangerine Mushroom (Agaricus trisulphuratus) is a visually captivating species. Its presence across diverse ecosystems highlights both its adaptability and ecological significance. Keep an eye out for this tropical beauty the next time you're exploring rich, organic soils!

🍽️ Edibility: The edibility of Agaricus trisulphuratus remains unknown. Exercise caution and avoid consumption.

🧐 Notable Observations

• Recorded in the Maasai Mara during June and in Thailand from May to August.

• Found growing under bamboo and in mixed forests.

• Type species of section Trisulphurati.

🔎 Identification

🍄 Cap:

• Shape: Starts hemispherical, transitions to convex, and flattens with age.

• Size: 30–60 mm in diameter.

• Surface: Dry and covered in triangular, orange to reddish-orange scales (squamules) arranged in concentric rings. These scales may wash off in wet conditions, leaving a felt-like texture.

• Color: Bright yellow, golden yellow, orange, or reddish-orange, fading with age or in rain.

• Margin: Initially curved inward and exceeding. 🌟🎨

🥩 Flesh: Firm and yellow, maintaining its color when bruised or cut.

🌿 Gills:

• Attachment: Free from the stem.

• Color: Begin pale purple, shift to reddish-brown or cinnamon brown as they mature.

• Arrangement: Crowded to very crowded.

📏 Stem:

• Size: 20–90 × 3–7 mm.

• Shape: Cylindrical, sometimes curved, hollow.

• Surface: Smooth and white above the ring; yellow and scaly below. The base is orange and scaly.

• Ring (Annulus): Yellow, faint, often blending with scales on the stem.

🦠 Spore Print: Brown to rust-colored.

🔬 Microscopic Features:

• Spores: Ellipsoid, reddish-brown, smooth, thick-walled, measuring 5–6 × 3.2–4 µm.

• Basidia: 4-spored.

• Cheilocystidia: Clavate to cylindrical, sometimes spiny.

👃 Odor: None to mildly mushroomy.

🧪 Chemical Reactions:

• KOH on cap: Yellow reaction.

• Schäffer’s reaction: Negative. ⚗️

🏞️ Habitat: Found in organic-rich soil, decomposed tree stumps, and shaded forest floors. It thrives in tropical and subtropical regions, appearing in forests, grasslands, and bamboo groves. Documented in areas such as Aberdare Forest, Kereita Forest, Maasai Mara, and Chiang Mai, Thailand. 🌳🌾

🌍 Ecology and Distribution: A saprophytic species of the Agaricaceae family, Agaricus trisulphuratus decomposes organic matter, playing a vital role in nutrient cycling. It has been observed in Africa, Malaysia, China, and Thailand, often found in solitary or small groups.

Photo sources:

Photo 1 - Author: Aravinth

Photo 2 - Author: J.M.Garg

Photo 3 - Author: Kristof Zyskowsk

Photo 4 - Author: i_c_riddell