Ling Chih is the Chinese term, and Reishi the Japanese term for fungi in the genus Ganoderma, section Ganoderma.
These fungi are important traditional health products in both cultures ( Ling Chih, for example, means "herb of immortality"), and in classical Chinese culture, liquor that the fungus had been soaked in was one of the standard accoutrements of a retired Chinese gentleman. I don't know how the Japanese have used it traditionally. In this country, people who have "rediscovered" its use tend to chop it up and boil it in water for long, long, long periods of time, a very different method of preparation. I don't know whether they invented that method themselves, on the theory that everything Chinese must be made into tea, or whether they got it from the Japanese.
