Heterobasidion annosum

Morphological Features:

Fruiting body sessile and perennial, emerging from the wood in a fan shape, resembling a crust attached to the wood itself. It usually measures over 10 cm in width and is not very thick, rather flat. It sometimes forms a single mass and at other times a cluster of several fruiting bodies. Near the point of attachment, it is dark brown, becoming reddish-brown towards the margin, which generally features a white growing zone.

Tubes arranged in several layers, approximately 5 mm thick per layer, cream-white in color.

Pores the same color as the tubes, small, numbering 2 to 5 per mm, round to angular.

Flesh very hard, tough, and leathery in consistency, cream-white in color, with a rather strong, sweetish odor.

Habitat:

This is a species exclusive to conifers that can be found practically year-round. It typically appears mainly at the base of stumps and damaged trees, often right at ground level, and as it grows, it envelops surrounding grasses and twigs.

Observations:

This species acts parasitically on the root zone of pines, i.e., where the pine bark meets the soil, as well as on the roots themselves. It penetrates deeply into the tree, causing a white rot and ultimately killing it, after which it behaves saprotrophically. Its dark crust-like appearance and white margin distinguish it from other similar species such as Antrodia serialis.