Community find

Oyster Mushroom

Pleurotus ostreatus (or similar species in the Pleurotus genus)

Group

gilled mushroom

Spore print

White to lilac-gray.

Size

Cap diameter 5-25 cm; stipe is typically 1-3 cm long or absent.

Season

Primarily spring and autumn, but can fruit during any warm spell in winter.

Habitat

Grows in clusters on dead or dying deciduous logs and standing trees, particularly hardwoods like oak, beech, and maple.

Distribution

Widespread throughout temperate and subtropical regions of the world.

Key characteristics

Fruiting bodies are shelf-like, fan-shaped, or kidney-shaped with decurrent gills that run down the stem when a stem is present. The surface is smooth, often ranging from white to grayish-brown. The gills are broad and tightly packed.

Fruiting body

Cap is 5-25 cm broad, fan-shaped, smooth, and convex to flat; gills are white to creamy, decurrent, and closely spaced; stipe is often absent or very short, thick, and lateral to the cap.

How to recognise it

Look for the shelf-like growth on wood, decurrent gills, and an anise-like or mushroomy scent. The spore print will be white to slightly lilac.

Look-alikes

Pleurotus pulmonarius (smaller, lighter, fruits in summer), Pleurotus populinus (grows on aspen/poplar), and Lentinellus ursinus (which has serrated gill edges and a very bitter taste).

Ecological role

Saprophytic (decomposes dead wood) and occasionally a weak parasite on living trees; it is also nematophagous, meaning it can trap and digest microscopic nematodes.

Notes

This fungus is one of the few known carnivorous mushrooms; its mycelium can kill and digest nematodes to obtain nitrogen in nutrient-poor wood environments. It is also used in bioremediation due to its ability to break down complex organic pollutants.