MushieField mushroom vs Yellow stainer: how to tell them apart
Both look like a classic white button mushroom. Scratch the base of the stem: a yellow stainer turns chrome-yellow within seconds and smells of ink or disinfectant, especially when cooked. A field mushroom never stains yellow like that.
Side-by-side comparison
 Agaricus campestris |  Agaricus xanthodermus | |
|---|---|---|
| Safety status | Edible (expert ID) | Poisonous |
| Cap | White, 3–10 cm, dry, smooth to finely scaly | White to greyish, 5–15 cm, smooth, often squarish in profile |
| Underside | Pink when young, chocolate-brown when mature, never white | Pink then chocolate-brown gills |
| Stem | Short, white, with a thin, fragile ring | White, bulbous base that turns chrome-yellow when cut or scratched |
| Smell | Pleasant, mushroomy | Like ink, hospital disinfectant or phenol (strongest when cooked) |
| Spore print | Dark brown | Dark brown |
| Habitat | Grazed pastures, meadows and lawns | Grass, parks, gardens and mixed woods |
| Season | Aug – Oct | Jun – Nov |
Photos: Wikimedia Commons contributor, CC BY-SA 3.0 · Velella, CC BY-SA 3.0
Quick tests that separate them
- Cut the stem base: bright yellow flesh = yellow stainer.
- Smell: ink, hospital or phenol smell = yellow stainer.
- Cap shape: yellow stainers are often square-shouldered, field mushrooms are more rounded.
- Gills: both start pink and turn chocolate-brown. White gills means neither, and may mean a deadly Amanita.
Key clues for each
Field mushroom: Pink gills in young specimens and chocolate-brown in old ones, and no yellow staining at the stem base or sac-like cup at the base.
Yellow stainer: Scratch the stem base: bright chrome-yellow flesh within seconds, and an ink-like smell. Cooking releases an unpleasant carbolic smell.
Frequently asked questions
How can I tell field mushroom from yellow stainer?
Both look like a classic white button mushroom. Scratch the base of the stem: a yellow stainer turns chrome-yellow within seconds and smells of ink or disinfectant, especially when cooked. A field mushroom never stains yellow like that.
Which is more dangerous, field mushroom or yellow stainer?
Yellow stainer (Agaricus xanthodermus) is the dangerous one. Causes gastrointestinal upset in many people. Often confused with edible field mushrooms.
Is it safe to identify mushrooms from photos or a website?
Never eat a wild mushroom based on an app or a website. Confirm identification and edibility in person with a qualified local expert.
Compare in the field
Photograph your find with Mushie to see possible matches and the look-alikes to rule out. Results are suggestions, never a safe-to-eat verdict.