Agaricus comtulus: The Ultimate Mushroom Guide

About The Agaricus comtulus Mushroom

Agaricus comtulus is a small cream color mushroom. In the British Mycological Society's list of English names of fungi, it is called Mini Mushroom; however, in the recent past it has often been referred to by the alternative English common name Ornamented Mushroom.

This widespread mushroom fruits in the parks, meadows, garden lawns, and other grassy habitats and occasionally in deciduous woodlands, either singly or in small groups. Found occasionally across much of mainland Europe, Agaricus comtulus is also recorded in some parts of Asia and North America.

Other names: Ornamented Mushroom.

Agaricus comtulus Identification

1. Pileus

   Cap 2.5-4 cm broad, convex-umbonate to convex when young, expanding to plano-convex; margin at first incurved, decurved at maturity; surface dry, cream-colored, appressed-fibrillose, seldom squamulose, the fibrils slowly becoming yellowish-brown to tawny with age or from handling, the disc usually darker; context white, firm, relatively thin, up to 4 mm thick, unchanging; odor of anise; taste pleasant, sweet.

2. Lamellae

   Gills free, crowded, thin, relatively narrow, at first pinkish, then pale greyish-brown, finally dark-brown; lamellulae up to 4-seried.

3. Stipe

   Stipe 3-5 cm long, 4-7 mm thick, stuffed at maturity, usually equal but occasionally with a small basal bulb or enlarged at the apex; surface silky-fibrillose, pallid, becoming tawny-brown with handling or in age; partial veil two-layered, consisting of small floccose scales over a thin membrane, rupturing to form an inconspicuous, pendulous, superior ring, in age appressed to the stipe.

4. Spores

   Spores 4.0-5.0 x 3.0-3.5 µm, broadly ellipsoid, smooth, thick-walled, hilar appendage inconspicuous, germ pore not evident, many spores with a dark central body; spore print dark-brown.

5. Habitat

   Solitary or in small groups in watered, grassy areas; fruiting from late summer to early fall; rare.

Agaricus comtulus Look-Alikes

1. Agaricus augustus

   Also smells of almonds but it is a much larger mushroom and is found with conifers.

2. Agaricus arvensis

   Similarities include a cream-colored cap that yellows slowly, a sweet anise odor, and a grassland habit.

3. Agaricus micromegathus

   Is another uncommon, grassland species. It is similar in size to Agaricus comtulus, yellows slowly, and is anise-odored, but according to Kerrigan has a cap which when young has "pinkish-red fibrils that darken to grey-brown" in age.

Agaricus comtulus Taxonomy & Etymology

Agaricus comtulus was first named and described scientifically in 1838 by the great Swedish mycologist Elias Magnus Fries, and the name that he gave it has remained generally accepted to this day, although in the interrim it has been given a few synonymous names including Psalliota comtula (Fr.), Pratella comtula (Fr.) Gillet, Fungus comtulus (Fr.) Kuntze, Agaricus niveolutescens Huijsman, and Agaricus huijsmanii Courtec.

The specific epithet comtulus, although misspelled, comes from a diminutive form of the Latin adjective comptus meaning combed, adorned or ornamented.