Scientific Name: Agaricus xanthodermus (Agaricaceae). 'Xanthodermus' means 'yellow skinned'.
English Name: Yellow Stainer; Yellow-staining mushroom (True mushroom family).
French Name: Agaric jaunissant (='yellowing mushroom').
5 Key Characters:
- white with pink to brown gills.
- rapidly turns bright yellow when damaged .
- globular when young, flattening out to a shallowly convex cap, 5 - 15 cm across.
- stem white, 1 - 2 cm in diameter, with obvious ring of persistent veil, bulbous at the base and rapidly yellowing if cut, especially at the base.
- smells of ink, phenol or iodine, especially after cutting and cooking.
Lookalikes: Field Mushroom Agaricus campestris, which does not stain yellow. Horse Mushroom Agaricus arvensis, which only slowly and slightly stains yellow, and smells of aniseed.
Habitat: Hedgerows, parks, gardens, especially along boundaries or in disturbed patches.
Fruiting Period: June-July-August-September-October.
Edible or Toxic? Causes serious digestive problems (nausea, cramps, sweating, vomiting, diarrhoea) and is a common cause of poisoning because it looks so much like Field Mushroom.
Photographed by Loire Valley Nature: