Pleurotus eryngii

The king oyster mushroom, growing in open grasslands on calcareous soils parasitizing or saprophytizing roots of Eryngium campestre, with a convex to flattened, fan-shaped pileus 5 to 10 cm across, cream to greyish-brown, inrolled margin, deeply decurrent white to pale orange lamellae, a short eccentric stipe, fungal odour, and sweet, pleasant taste.

Pileipellis composed of slightly interwoven cylindrical hyphae 4 to 6.5 µm wide, thin-walled, hyaline or containing pale brown intracellular pigment, with some emergent rounded terminal cells, septate with prominent clamp connections.

Cystidia and other sterile hymenial elements absent.

Basidia cylindrical-clavate, 40 to 60 µm long, 6 to 8 µm wide, clamped at the base, 4-spored.

Spores cylindrical-ellipsoidal, smooth, hyaline, thin-walled, 9.5 to 11 µm long, 4 to 5.5 µm wide, with an eccentric apiculus at one end, containing small guttules, inamyloid in Melzer's reagent.