The wild variety A. bisporus var. bisporus is the type variety of the species and is characterised by secondary homothallism. Wild specimens of it have been collected in large numbers in Europe (France, Greece, Israel, the United Kingdom and elsewhere) and North America, and the specimens also included strains from China.
The variety A. bisporus var. burnettii (Kerrigan & Callac 1993) is a heterothallic variety described from the Sonoran Desert in California; its studied strains come from the United States.
The variety A. bisporus var. eurotetrasporus (Callac & Guinb 2003) is a homothallic variety known from rare specimens recorded in Europe; its two studied strains come from France and Greece.
Approved version OWNER-REVIEW-20260930T094901862 · last approved 30 September 2026
"Horst U1" is the first commercial hybrid strain, developed in 1980 by crossing two old cultivars, white and off-white, and it is currently the main commercial strain, together with the hybrid "U3". Before that, the types in circulation in the 1970s numbered about six: white, off-white, small white, golden white, brown and small brown.
