Fungi Agaricus arvensis, commonly referred to as the "Horse Mushroom," is a fascinating and widely encountered mushroom species. In the region of the Comunidad Valenciana, you might hear it being called "Champiñón de Campo" due to its local importance and recognition.

This mushroom is distinguished by several key features:

• Cap: The cap is large and can range from 5 to 20 cm in diameter. It starts as a rounded shape and flattens out as it matures, with a white to cream color. As it ages, the cap may develop scales or become slightly yellowish.
• Gills: The gills of the Agaricus arvensis are free, densely packed, and transition in color from pink to brown as the mushroom ages.
• Stipe (Stem): The stem is robust, white, and often has a slight bulbous base. A distinctive characteristic is the presence of a large, double-edged ring near the top of the stem.
• Spore Print: The spore print of this mushroom is chocolate brown, which is typical of many species in the Agaricus genus.
• Odor: The Horse Mushroom emits a pleasant, sweet, anise-like scent, especially noticeable when it is freshly picked.

Agaricus arvensis typically thrives in grasslands, meadows, and pastures. It is a saprobic organism, obtaining its nutrients from decaying organic matter, which makes it an important part of the ecosystem, contributing to the decomposition and nutrient cycle.

While it is considered edible and enjoyed by many for its mild flavor, it's crucial to be cautious and properly identify this mushroom, as it can be confused with toxic species of similar appearance. As always, when foraging, consult local experts or guides to ensure safe and responsible mushroom collection.