“…Neither was the mycelium suitable as spawn (Humfeld, 1950(Humfeld, -1951. Because of many physiological and morphological differences between the NRRL-strains and other strains of the cultivated mushroom, Molitoris (1962 and1963) studied the NRRL strains taxonomically and identified them as Beauveria tenella, an imperfect fungus which may occur on the cap ofA. bisporus.…”