Albatrellus confluens

Albatrellus confluens is a terrestrial polypore in the family Albatrellaceae (order Russulales), commonly called the common earthfan or confluent earthfan. Rather than producing gills, it bears a white to cream pore surface beneath a fleshy, cream to ochre-brown cap. The caps of neighbouring fruitbodies frequently merge, a habit reflected in the epithet confluens. It fruits on the ground in coniferous forests of the Northern Hemisphere, where it is associated with conifers as an ectomycorrhizal partner. Its edibility is poorly documented and it is generally treated as inedible, but it has drawn scientific attention as a source of bioactive secondary metabolites.

History

The species was described by Albertini and Schweinitz and later transferred to the genus Albatrellus by Kotlaba and Pouzar, giving the accepted name Albatrellus confluens (Alb. & Schwein.) Kotl. & Pouzar. The genus name derives from Latin albus ("white"), referencing the pale pore surface and flesh typical of these polypores, while confluens refers to the way adjacent caps grow together. Interest in the species increased markedly in the early 2000s when researchers in China and Japan isolated and characterised its bioactive compounds.

Overview

Unlike bracket fungi that decay wood, A. confluens is a ground-dwelling, mycorrhizal polypore of conifer forests, and is not cultivated commercially. Its main significance is chemical: the phenolic meroterpenoid grifolin isolated from its fruitbodies has been shown in laboratory studies to inhibit the growth of several human cancer cell lines and to induce apoptosis (Ye et al., 2005; 2007), partly through suppression of the ERK1/2 signalling pathway. A related compound, albaconol, has also been studied for its biological activity. These findings concern isolated compounds in laboratory settings and are not evidence of culinary value or of any proven medical use; the mushroom itself is not recommended for eating.