These jolly mushrooms are called Volvariella volvacea. Their common name comes from the rice straw on which they are grown. The straw mushroom, also called paddy straw mushroom, is cultivated in the hot, steamy climate of Southeast Asia. Attempts to grow them in the southern United States so far have been unsuccessful. They are not widely eaten in the United States, but worldwide they rank third in consumption, just behind Agaricus bisporus (the common store mushroom) and Lentinus edodes (shiitake). Indeed, straw mushrooms have been used for food in China for two thousand years.