Sweet chestnut and other deciduous broadleaved species.
At the base of the tree and on structural roots.
Annual. often grows in clusters. Dark tan-brown caps usually around 5cm across though sometimes more pale brown. Gills visibly widely-spaced and are off-white to beige-brown. Stem is shaped like a spindle and is darker brown at the base and lighter brown where it meets the gills. White spore. May appear as blackish fragments in over-maturity at the base of the host tree.
Armillaria spp. (much larger in size and often abundance).
Research suggests that this fungus can act as a parasite on the roots and root collar of the host tree (even trees with high vitality), which leads to root mortality. Because of root mortality, this fungus may impact upon the physiological and structural condition of the host tree, wherein the crown may show symptoms of dieback and the tree may pose an increased risk to targets. Therefore, where this fungus is found, further investigations in to tree stability and crown management may be required. It is not considered likely that this fungus can spread via root-to-root contact. Considered to be more virulent in drier soils and to be generally rather averse to waterlogged conditions.