Mushroom

A bittercap mushroom (or bittercap) is a type of fungus, they have a few different uses.

Obtaining bittercap mushrooms
It may be grown from a bittercap mushroom spore (taking up to 240 minutes to grow) by players with level 53 Farming in the mushroom patch near Canifis. This may yield up to six mushrooms. You do not need a spade in your inventory to harvest this item.

Uses

 * Mushrooms may be added to a compost bin to make supercompost (requiring 15 mushrooms, or a combination of supercompost items).
 * Five mushrooms are used to activate the fairy ring in the Ancient Cavern.
 * Eight mushrooms may be used to pay a farmer to look after a whiteberry bush.
 * Four mushrooms are the main ingredient for brewing Moonlight mead.
 * They can be used to make fried mushrooms.