Oyster mushrooms, also known as oyster caps, tree mushrooms, tree oyster mushrooms, summer oyster mushrooms, pleurotte and shimeji, are fan-shaped mushrooms that grow both wild and cultivated, usually on rotting tree trunks.
The cap can vary in color from pale gray to dark brownish-gray with grayish-white stems. While raw oyster mushrooms have a robust and slightly peppery taste, cooking mellows their flavor substantially.
Oyster mushrooms are an excellent source of niacin and riboflavin and contain the phytonutrients beta-glucan and L-ergothioneine.