Field mushroom Agaricus campestris

Right now

When to look

From August to October. Favourable temperatures: 12 to 20 °C. It usually fruits 3 to 9 days after at least 12 mm of rain.

Where to look

Habitat

Grazed pasture, lawns (untreated)

Soil

Rich neutral soils (grassland) (pH 6.0 to 7.5)

How to recognise it

Cap 4 to 10 cm, pure white then greyish white or slightly pinkish, dry, silky to finely fibrillose, with a margin inrolled at first. Gills free, bright pink when young, turning chocolate brown at maturity (spore print dark brown): they never stay white. Stem short, white, solid, tapering at the base, with no volva or bulb, bearing a thin, single ring that soon disappears. Flesh white, barely pinking, pleasant mushroom smell, neither of ink nor of phenol. Fruits in the short grass of meadows and pastures, away from woods.

Dangerous look-alikes

• Death cap

  Amanita phalloides
  deadly

  Gills staying white at every age and spore print white, cap olive green to greenish brown (sometimes creamy white in the variety alba), persistent white membranous ring and above all the base of the stem sheathed in a sac-like volva, which has to be dug out to be seen: the field mushroom never has one. It grows under trees, broadleaves (beech, oak) as well as conifers (spruce, fir, pine), and not in open meadow. Around thirty grams is enough to kill an adult.

• Destroying angel

  Amanita virosa
  deadly

  Entirely white, and therefore even more deceptive: cap white to ivory, often truncated-conical and irregular, gills free and staying white, spore print white, stem slender and flocculose-shaggy, with a fragile ring and a sac-like volva at the base. Non-chalky soils, under broadleaves or conifers, never in the short grass of pastures. Always gather the whole mushroom, stem included, and reject any ‘field mushroom’ with white gills.

• Spring destroying angel

  Amanita verna
  deadly

  The third deadly white amanita, and the earliest: it appears from May until the end of summer, when the first field mushrooms are already being picked. Cap 4 to 8 cm, plain white to ivory, with a thin, unstriated margin; gills free and staying white, spore print white; persistent white membranous ring; white stem ending in a spherical bulb sheathed in a sac-like volva. A warmth-loving species of open oak and sweet chestnut woodland on acidic, sandy soils, never in open short-grass meadow. Its taxonomic rank is disputed — several authors see it only as a white form of the death cap, and the distinction rests on a chemical reaction with potassium hydroxide, unusable in the field: one more reason to discard as a whole any white mushroom with white gills and a sheathed stem base, without trying to name the amanita.

• Yellow stainer

  Agaricus xanthodermus
  poisonous

  The flesh yellows vividly and immediately when scratched, especially at the base of the stem split lengthwise, and gives off a smell of ink or phenol that grows stronger on cooking. Its ring is large and persistent.

Foraging tips

Dig up the whole stem to check that there is no volva, then split the base of the stem: any vivid yellowing or any smell of ink means the gathering must be discarded. The deadly white amanitas do not form a closed list: the death cap in its white form, the destroying angel, the spring destroying angel, and intermediate forms that specialists themselves debate. The rule must therefore not try to name them: white gills, a white spore print or a sheathed stem base mean the entire gathering must be discarded, whatever the mushroom's name. Avoid treated meadows or those bordering a road (the species accumulates heavy metals) and eat cooked within two days.

Model reliability

Reliability for this species: moderate.

Also in season

• Chanterelle
• Cep (penny bun)
• Parasol mushroom
• Horn of plenty
• Winter chanterelle
• Hedgehog mushroom

Where mushrooms are fruiting this week · All species