Pisolithus

Pisolithus is a genus of fungi belonging to the order Boletales. These fungi are characterized by their unusual fruiting bodies, which are often described as spherical or irregularly shaped and composed of numerous small, hard, spore-bearing cavities. The outer layer of the fruiting body, known as the peridium, is typically tough and fibrous. When mature, the fruiting bodies often break open, revealing a powdery mass of dark brown to black spores. The internal structure is distinctly chambered, giving it a segmented appearance.

Pisolithus species are commonly found in terrestrial environments, often associated with trees, particularly pines and eucalyptus. They are ectomycorrhizal fungi, meaning they form a symbiotic relationship with the roots of plants. This association benefits the plant by increasing its access to water and nutrients from the soil, while the fungus receives carbohydrates from the plant. Pisolithus species are widespread and can be found in various habitats, including forests, woodlands, and disturbed areas. They are not typically considered edible and are known for their hard, stony texture. Identification of specific species within the genus often relies on microscopic examination of spores and internal structures.