Shiitake is grown on oak logs in the wild, hence its name "Shii" (oak tree) "take" (mushroom). In the more modern mushroom farms, Shiitake mushrooms are grown in plastic-bag logs filled with wood substrate and have become one of the most popular cultivated mushrooms. It is known to enhance the immune system, aiding the body to fight infection and disease, and is gaining ground in the medical world for its anti-tumor qualitites.