How to tell Agaricus romagnesii from Inky mushroom
How they differ, how to recognize them and which is more dangerous — a mushroom comparison
Warning: Inky mushroom(Agaricus moelleri)
POISONOUS
Eating it causes poisoning. Do not pick it unless you have identified it with certainty.
Contains phenolic gastrotoxins, similar to those of the yellow stainer (A. xanthodermus). Causes acute gastroenteritis: nausea, repeated vomiting, abdominal pain, diarrhea 1-6 hours after eating. Symptoms last 12-24 hours. Not fatal, but unpleasant and potentially dangerous due to dehydration, especially for children.
As with the yellow stainer, some people (around 50%) have a genetic tolerance and don't react to the toxins. The rest react with acute symptoms. There's no way to know your sensitivity in advance. Our rule: don't eat it.
Treatment is symptomatic: gastric lavage (within the first 2 h), activated charcoal, IV fluids for dehydration, antiemetics. Recovery usually takes 1-2 days.
If you suspect poisoning, call an ambulance immediately: 112 (the European emergency number) or your local emergency number
The short answer
Agaricus romagnesii and Inky mushroom look alike, so they're easy to mix up — but Agaricus romagnesii is edible, while Inky mushroom is poisonous. The main visible difference: use: Agaricus romagnesii — cook fresh, pickling, Inky mushroom — not eaten. The mushrooms also differ in the following features: cap color, taste, smell. If you have even the slightest doubt, leave the mushroom be.
Agaricus romagnesii
Agaricus romagnesii
Inky mushroom
Agaricus moelleri
📊 Comparing characteristics
⚠ Highlighted rows are the key differences between the edible and the dangerous mushroom
| Characteristic | Agaricus romagnesii | Inky mushroom |
|---|---|---|
| ⚠ Edibility class | Agaricus romagnesii Edible | Inky mushroom Poisonous |
| Season | Agaricus romagnesii SummerAutumn | Inky mushroom SummerAutumn |
| ⚠ Use | Agaricus romagnesii Cook freshPickling | Inky mushroom Not eaten |
| Size | Agaricus romagnesii Medium (5–15 cm) | Inky mushroom Medium (5–15 cm) |
| ⚠ Cap color | Agaricus romagnesii BrownCream | Inky mushroom WhiteGreyBrown |
| Cap shape | Agaricus romagnesii Convex | Inky mushroom Convex |
| Cap surface | Agaricus romagnesii Scaly | Inky mushroom Scaly |
| ⚠ Taste | Agaricus romagnesii Mild | Inky mushroom Unknown |
| ⚠ Smell | Agaricus romagnesii PleasantAlmond | Inky mushroom Chemical |
| ⚠ Flesh color change | Agaricus romagnesii Reddening | Inky mushroom Yellowing |
| Hymenophore | Agaricus romagnesii Gilled | Inky mushroom Gilled |
| ⚠ Stem | Agaricus romagnesii Central | Inky mushroom Bulbous |
| Ring (veil) | Agaricus romagnesii Ring present | Inky mushroom Ring present |
| Volva | Agaricus romagnesii No volva | Inky mushroom No volva |
| Substrate | Agaricus romagnesii SoilForest litter | Inky mushroom SoilForest litter |
| Nutrition type | Agaricus romagnesii Saprotroph | Inky mushroom Saprotroph |
| Partner trees | Agaricus romagnesii OakBeechHornbeam | Inky mushroom BeechHornbeamOak |
📅 Seasonality
Agaricus romagnesii
Fruiting season
August – October
Inky mushroom
Fruiting season
June – October
🔬 Morphology
Cap
Agaricus romagnesii
Cap 6-15 cm across; in young mushrooms hemispherical to egg-shaped, later becoming convex to flat. Color brownish-cream to grayish-brown, with distinct small brown or dark brown scales in the center and middle zone. The surface is dry, slightly sticky in wet weather.
Inky mushroom
Cap 5-10 cm across; in young mushrooms hemispherical to conical-convex, later convex with a low umbo. Color whitish to grayish, with distinct, radially arranged small gray-brown or blackish-gray scales — a hallmark of the species (unlike the yellow stainer, whose cap is smooth). When touched, the cap yellows to chrome yellow, like the yellow stainer's.
Hymenophore
Agaricus romagnesii
Gilled hymenophore — gills free, crowded. When young — pale pink, becoming with age dark brown, chocolate-blackish. Spore print dark brown.
Inky mushroom
Gilled hymenophore — the gills are free, crowded. In young mushrooms — pale pink to grayish-pink, with age they become dark brown, chocolate-blackish. Spore print dark brown.
Stem
Agaricus romagnesii
Stem 8-12 cm tall, 1-2 cm thick, cylindrical, slightly thickened at the base. Color white to cream, with fine brownish fibers below the ring. On the upper part — a white membranous ring, distinct in young mushrooms.
Inky mushroom
Stem 5-10 cm tall, 0.8-1.5 cm thick, cylindrical, with a bulbous base. Color white. When cut, the flesh in the lower part of the stem turns bright chrome yellow — just like the yellow stainer, the same diagnostic feature. In the upper part — a white membranous ring.
Flesh
Agaricus romagnesii
Flesh firm, white; when cut it slowly turns pinkish to brownish. Does not turn chrome yellow (the test against the yellow stainer). The smell is pleasantly mushroomy with a subtle almond-anise note.
Inky mushroom
Flesh firm, white, turns bright chrome yellow when damaged, in the lower stem and in the flesh of the bulb. Smell distinct and unpleasant — ink, phenol, pharmacy ointment, creosote.
Smell
Agaricus romagnesii
Pleasantly mushroomy, with a subtle almond-anise note. It doesn't smell of ink or medicine.
Inky mushroom
Distinctly unpleasant, with notes of ink, phenol and pharmacy ointment — like the yellow stainer. It comes out when you rub the flesh.
📍 Habitats
Agaricus romagnesii
Inky mushroom
👀 Similar mushrooms — don't mix them up!
❓ Frequently asked questions
Can Agaricus romagnesii and Inky mushroom be mixed up?
How to tell Agaricus romagnesii from Inky mushroom?
Which is more dangerous — Agaricus romagnesii or Inky mushroom?
Is Inky mushroom edible?
When do Agaricus romagnesii and Inky mushroom grow?
Sources
- [1]Вікіпедія (українська)
- [2]Атлас грибів України, Зеров Д.К. (1979)
- [3]MycoBank Database
- [4]Index Fungorum
- [5]GBIF
- [6]iNaturalist Ukraine