Agaricus is the leading mushroom crop worldwide and accounted for 99% of the United States’ mushroom production in 1997. The oyster mushroom (Pleurotus spp.) has been domesticated more recently and now ranks second in world production. The Shiitake mushroom, which is very popular in Asian cultures, ranks third in world production. Many other edible mushrooms, such as the straw mushroom (Volvariella volvacea) and wood ear mushrooms (Auricularia auricula), are gaining in popularity. It is estimated between 650-700 mushroom species are edible, but only approximately 130 have been domesticated. Increased demand for specialty mushrooms has been particularly strong. Asian countries continue to dominate world production and consumption; however, consumption in the United States has increased sharply in recent years, providing potential opportunities for mushroom growers.