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Grey oyster - Pleurotus ostreatus

Grey Oyster - Pleurotus ostreatus

Main features

  • Fruits Summer to Winter

  • Grows on dead or dying deciduous wood

  • Smells mildly of mushrooms

  • Cap grey, blue-grey, cream or brown with a wavy edge

  • Cap between 10 and 18cm and has a depression in older specimens

  • Short stem at the side of the cap or offset

  • Gills are white turning pale cream and run decurrently down the stem

  • Flesh is white

  • Spore print is white to pale lilac-grey

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Grey Oyster - Pleurotus ostreatus

Edible mushroom - novice

Other common names: Tree Oyster


Scientific name meaning: The genus name comes from the Greek Pleura, meaning "a rib" "the side", and in reference to how the stem is at the side of the mushroom. Ostreatus is from the Latin Ostrea, meaning an oyster

Season - when will I find it? Summer to Winter

Habitat - where will I find it? Grows on the wood of dead or dying  deciduous trees

Description - what does it look like? 

Growth: The Grey Oyster is a saprobic, sometimes weakly parasitic, mushroom living on dead or dying deciduous wood. It grows in overlapping groups

Cap: The cap is between 5-18cm across and can be grey, blue-grey, cream or brown. It is shaped like a fan or shell with a wavy edge on larger specimens. As it ages, a depression forms in the cap

Gills: The gills start off white, becoming a pale cream colour. They are crowded and decurrent (running down the stem)

Flesh: The flesh is white

Stem: Is short and to the side of the cap or offset. Each stem is separately attached to the substrate

Smell: Mild mushroom smell

Spore colour: White or pale lilac-grey

Possible lookalikes Could be confused with Angels Wings (Pleurocybella porrigens), which is now know to be toxic. However, this is a very white colour and grows on coniferous wood. It also prefers slightly colder temperatures, so unusual to find south of Scotland in the UK. Oysterlings may also be confused with Oysters Mushrooms, but the largest of these reaches around 6cm. To rule them out, only harvest Grey Oysters with caps of 8-10cm or larger

Use as a food A popular cultivated as well as a wild mushrooms, the Grey Oyster is used in a wide range of mushroom dishes

Use in herbal medicine The Grey Oyster is believed to boost brain health, help with inflammation, reduce cholesterol and inhibit cancer growth

If you are suffering from any ailment or need medical advice, please see your General Practitioner

Hazards None known

Things to note Oyster Mushrooms catch and feed on nematode worms living in their substrate. They are cultivated in the same way as Grey Oysters, and grown on coffee grounds, sawdust, newspapers and old books

Importance to other species Provides food for a the larvae of a number of fly species. Worth remembering when harvesting. Younger, fresher specimens tend to have less livestock inside! 

Also a food source of slugs

Always stay safe when foraging. You need to be 100% sure of your identification, 100% sure that your foraged item is edible, and 100% sure that you are not allergic to it (it is good practice to always try a small amount of any new food you are consuming). If in doubt, leave it out!

Grey Oyster - Pleurotus ostreatus gills
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