Polyozellus is a genus of fungi in the family Thelephoraceae, a grouping of mushrooms known collectively as the leathery earthfans. A monotypic genus, it contains the single species Polyozellus multiplex, first described in 1899, and commonly known as the blue chanterelle, the clustered blue chanterelle, or, in Alaska, the black chanterelle. The distinctive fruit body of this species resembles blue- to purple-colored clusters of vase- or spoon-shaped caps with veiny wrinkles on the undersurface that run down the length of the stem.
Polyozellus has had a varied taxonomic history and has been reclassified several times at both the family and genus level. The range of Polyozellus includes North America and eastern Asia, where P. multiplex may be found growing on the ground in coniferous forests, usually under spruce and fir trees. It is an edible species, and has been harvested for commercial purposes. Polyozellus multiplex contains the bioactive compound polyozellin, shown to have various physiological properties, including suppressive effects on stomach cancer.