Laurence asked: “Is it true that cultivated mushrooms are all the same species?”
Not all. But a few of the common fresh mushrooms we love are all varieties of one species, Agaricus bisporus.
Many species of mushrooms can’t be successfully grown in captivity, at least not on a commercial scale, but A. bisporus was first cultivated centuries ago in Europe. The mushrooms were small, mild-tasting (especially when grown on a mild-tasting medium), and brown-skinned: They’re what we call cremini today.
Their ease of growing plus their deliciousness made them very popular—until 1925, when a Pennsylvania mushroom farmer named L. F. Lambert found a mutant strain among his A. bisporus crop. In a sea of brown mushrooms, this one was white as snow.
Lambert propagated the new mushroom and sold it under the name “Snow White.” With its clean, appealing appearance, the white button mushroom rapidly displaced the brown variety and became the dominant mushroom, making up 90 percent of U.S. mushroom consumption today.