Giant Polypore Fungus

Scientific name: Meripilus giganteus

Common name: Giant Polypore

Type of decay: White rot, sometimes soft rot

Family: Meripilaceae

Description

Meripilus giganteus is and annual fan-shaped bracket that appears at the base of stems and the roots of trees, visible between August – October. The bracket clusters can grow up to 50-60cm across, with individual caps 5-20cm across. It begins with yellow-brown smooth brackets often radially streaked and concentrically zoned. The brackets cluster together and overlap each other. The underside fronds consist of cream coloured tubes that become blackened when bruised. The spore powder of this bracket is white. (Meripilus giganteus can often be confused with Grifola fondosa)

Effects of fungus on tree:

Decay only affects the roots where white rot makes the root timber go brittle and then later soft. This will lead to brittle fracture of the roots near to the stem and failure of the tree at this point. Decay is normally restricted to the deeper roots. It rarely extends into the lower trunk. This makes the detection of wood decay with the use of diagnostic devises difficult. Meripilus giganteus can cause crown thinning, small and pale leaves, late leaf growth and early leaf shedding. Decayed branches may fall before or after the foliage dies.

Hosts: Most commonly associated with Beech but also found on Oak, London Plane, Sycamore and Lime.