Description
The king oyster has a thick, fleshy, white stem 3-10 cm tall and a relatively small, tan to brown cap 4-15 cm across, smooth or slightly velvety. The gills are whitish, crowded and decurrent. It grows not on wood but on the roots of plants of the carrot family, especially field eryngo.
In Europe it occurs naturally mainly around the Mediterranean. In Poland only one doubtful, historical site is known, and since 2014 the species has been under strict protection, so it must not be collected in Poland. Only a cultivated specimen or one from outside Poland is allowed on the market.
The mushroom is widely cultivated and sold as the king oyster mushroom. If you are not sure of the species, do not pick or eat it.
Identification features
- Cap
- Diameter 4-15 cm, tan (light brown), smooth, slightly velvety; convex, then flattened, with a thin margin at first rolled under, later spread out. The cap is relatively small compared with the thick stem.
- Hymenophore (underside of the cap)
- Gills whitish, decurrent, crowded, connected by anastomoses (veins).
- Stem
- Height 3-10 cm, thickness 1-3 cm, white (thick, fleshy, white); usually central or slightly off-centre. No data on a ring or on the base.
- Flesh
- No detailed description.
- Spore print and spores
- No data (spore print colour and spore dimensions are not given).
Habitat and distribution
Ecology. Unlike most oyster mushrooms (wood decay), the P. eryngii complex is a weak parasite on the roots of herbaceous plants of the carrot family (Apiaceae), especially field eryngo (Eryngium campestre); it is also described as a saprotroph and can be cultivated on organic waste. The mycelium captures and digests nematodes.
Distribution. Natural range from the Atlantic through the Mediterranean basin (with North Africa) and Central Europe to Western Asia and India. In Poland only one historical and doubtful site is known (near Elbląg, 1916, Kaufmann). Since 2014 under strict protection in Poland.
Fruiting. No data.
What can it be confused with?
- Pleurotus nebrodensis — According to molecular studies a closely related but distinct species; details - no data.
- Pleurotus fossulatus — May be closely related; details - no data.
- Pleurotus ostreatus (oyster mushroom) — Cultivated similarly and related; the oyster mushroom grows on broadleaved wood, not on the roots of herbaceous plants; cap more shell-shaped, stem shorter. Details - no data.
Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.
Interesting facts
- The species name comes from the host plant, eryngo (Eryngium), on whose roots it grows.
- The only Polish site (near Elbląg, 1916) was reported by Kaufmann, but his identification is doubtful.
- The mycelium captures nematodes, and phylogenetic analyses suggest that this way of feeding has a very long evolutionary history.
Frequently asked questions
When does King Oyster grow?
According to observations in Poland (GBIF) the season is: September – December; most records fall in November.
Where does King Oyster grow?
Unlike most oyster mushrooms (wood decay), the *P. eryngii* complex is a weak parasite on the roots of herbaceous plants of the carrot family (Apiaceae), especially field eryngo (*Eryngium campestre*); it is also described as a saprotroph and can be cultivated on organic waste. The mycelium captures and digests nematodes.
Is King Oyster protected?
Yes, it is a protected species in Poland — leave it in the forest and only take a photo.
In the Gribo app this species also has a 3D model you can rotate, photos in the quiz and warnings when identifying with the camera. See how to get started.