- noun a fungus which primarily attacks trees and shrubs. Roots become infected by rhizomorphs. In the spring the foliage wilts and turns yellow.
- A fungus, Armillaria mellea, which is a garden pest and grows on live trees causing them to wilt and die. The cap is golden brown when young, becoming lighter as it ages. The slender stem curls out from a swollen base attached to the tree trunk. Although edible it has a bitter taste and unpleasant smell and is not recommended.