Pisolithus Arhizus

Pisolithus arhizus, commonly referred to as the Black Jelly Roll, Dead Man’s Foot, or Dyeball, is a large, earthball-like ectomycorrhizal fungus known for its unique spore-sack structure and strong symbiotic relationships with trees. Though not edible due to its tough, gritty texture, it plays a vital ecological role and is especially valued for its use in mycorrhizal inoculants and natural dyeing.

History

Often found in poor, sandy soils and disturbed areas, this fungus has been used in restoration ecology for decades due to its ability to help trees establish in nutrient-poor or degraded environments. Its dark, spore-rich interior was traditionally used by Indigenous Australian communities as a natural dye for fabric and fibers.

While not historically used for food or medicine, P. arhizus is widely studied for its environmental and biotechnological applications.

Overview

The fruiting body of Pisolithus arhizus resembles a dark brown or black potato-shaped lump up to 10–20 cm across. When young, it contains gelatinous, marble-like peridioles (spore packets) that give rise to the nickname “Black Jelly Roll.” As it matures, the peridioles rupture and release vast quantities of brown powdery spores.

This species forms mutualistic relationships with the roots of a wide range of trees, including pines, oaks, and eucalyptus. It's often added to soil as a mycorrhizal inoculant to boost tree health, drought resistance, and nutrient uptake. It is not edible or psychoactive, but holds high ecological and commercial value.