Oyster Mushroom – Pleurotus ostreatus

Fungi of the Week

17th April 2020 | Info

Common name: Oyster Mushroom 

Scientific name: Pleurotus ostreatus  

Introduction: The Oyster Mushroom (Pleurotus ostreatus) is a large fungus that is commonly found in woodlands.  


Cap: Oyster Mushroom caps have a distinct fan-like shape that resembles the likes of an oyster (hence the name!). They can vary in size, typically forming between 5-25cm and can vary in colour. Usually, when young, the cap of an Oyster Mushroom is almost black in colour which then develops into a grey colour in the winter months. However, throughout the rest of the year, they are a white-grey, but some patches may have a slight tan tint. They can also occasionally be lobed or wavy.  

Gills: The gills of an Oyster Mushroom form on the underside of the fruiting body and are typically creamy white. They tend to vary in thickness, depending on the age of the fruiting body, and unite near the base of the fungi. 

[Gills of an Oyster Mushroom]

Stem: Sometimes, the Oyster Mushroom will be stemless; however, they can also occasionally have short thick stems that can form off-centre.  

Spores: Subcylindrical to a narrow kidney-like shape and have a white/grey spore print.   

Flesh: Soft and thick. 



Growing on a range of deciduous broadleaf trees, you can commonly find the Oyster Mushroom in woodlands. They are a non-persistent and form annually, usually between late autumn and winter. Typically, you will find that they form in clusters which can give off a bracket-like appearance. However, they can also form singularly.  

Impact on Trees

Oyster Mushrooms can sometimes be weakly parasitic; however, they commonly tend to be more saprobic. Mainly, you will find that main stems and principal roots are the most affected areas by the Oyster Mushroom. They cause decay to typically form on or around a wound-site which initially causes delignification of earlywood and then develops into an intense white rot. 

Want to get listed on Directree?

Are you a tree surgeon? Click the button to claim your free listing and see our other membership options today!

Are you looking for a tree surgeon?

Are you looking for a professional in your area to help you? Click the button to search our database today!