the fungus grows predominantly in coniferous forests, forming symbiotic ectomycorrhizal associations with living trees by enveloping the tree's underground roots with sheaths of fungal tissue. the fungus produces spore-bearing fruit bodies above ground in summer and autumn. the large, edible fruiting bodies known as mushrooms appear under pine trees, generally in summer and autumn. it has a matte brown to maroon-coloured cap and its stem is often large and swollen, and the overall colour may have an orange-red tinge. as with other boletes, the size of the fruiting body is variable.