Leucoagaricus americanus

🏷️ Description

Leucoagaricus americanus, commonly known as the American parasol, is a mushroom in the genus Leucoagaricus, native to North America.

🛤️ Habitat & Distribution: This urban-loving mushroom thrives on wood chips, sawdust, and stumps, often appearing in landscaping areas, parks, and waste places. While common east of the Rocky Mountains, it is rare in the western U.S. and the U.K.

🌱 Season & Growth: Typically found in late summer to autumn, but occasional finds have been recorded in warmer greenhouse environments during winter.

🔎 Identification

🍄 Cap: 1.18 to 5.91 inches (3 to 15 cm), starting as a smooth, white oval before breaking into reddish-brown scales. It blushes pinkish-red when handled or as it matures!

🍂 Gills: Free from the stem, creamy white at first but deepening to pinkish-maroon over time.

🌱 Stem: 2.76 to 5.51 inches (7 to 14 cm) tall, often spindle-shaped, smooth and silky. Initially white, it stains yellow before turning reddish-brown. A fleeting white ring decorates the upper stem.

🩸 Flesh: Thick and white, bruising yellow to orange when young, then drying to a deep reddish-brown.

🔬 Spores: White spore print; smooth, elliptical spores (8–11 × 6–7.5 µm).

⚗️ Chemical Reactions: KOH turns fresh cap surfaces red, while ammonia may create a green reaction.

🚫 Edibility: Though reported as edible, it's not recommended due to potential confusion with toxic lookalikes like Chlorophyllum molybdites!

🌎 Habitat: Grows alone, scattered, or in groups near wood debris, old stumps, and waste areas. A frequent summer and fall guest in urban and natural landscapes.

👀 Look-Alikes

1. Chlorophyllum molybdites: A large, scaly-capped species with green spores, known to cause severe gastrointestinal distress.

2. Lepiota helveola and Lepiota josserandii: Small, toxic mushrooms that contain the same deadly toxins as the Death Cap (Amanita phalloides).

📜 Synonyms

• Agaricus americanus Peck (1872)

• Agaricus lazulinoides Schulzer (1878)

• Agaricus cupreus Schulzer (1878)

• Agaricus bresadolae Schulzer (1885)

• Lepiota haematosperma Quélet (1886)

• Lepiota bresadolae (Schulzer) Saccardo (1887)

• Lepiota americana (Peck) Saccardo (1887)

• Pseudofarinaceus bresadolae (Schulzer) Kuntze (1891)

• Mastocephalus bresadolae (Schulzer) Kuntze (1891)

• Mastocephalus americanus (Peck) Kuntze (1891)

• Fungus bresadolae (Schulzer) Kuntze (1898)

• Lepiota badhamii ss. Konrad & Maublanc (1925)

• Leucoagaricus bresadolae (Schulzer) Bon & Boiffard (1977)

• Leucocoprinus bresadolae (Schulzer) M.M. Moser (1978)

• Leucocoprinus americanus (Peck) Redhead (1979)

Photo sources:

Photo 1 - Author: Annie Weissman (Public Domain)

Photo 2 - Author: Tom and T Herman (CC BY 4.0)

Photo 3 - Author: Michael Hinczewski (CC BY 4.0)

Photo 4 - Author: snake venom (CC BY 4.0)