The lingzhi mushroom or reishi mushroom encompasses several fungal species of the genus Ganoderma, and most commonly refers to the closely related species, Ganoderma lucidum and Ganoderma tsugae. G. lucidum enjoys special veneration in East Asia. it has attained a reputation in the East as the ultimate herbal substance. Lingzhi is listed in the American Herbal Pharmacopoeia and Therapeutic Compendium. Lingzhi is a polypore mushroom that is soft (when fresh), corky, and flat, with a conspicuous red-varnished, kidney-shaped cap and, depending on specimen age, white to dull brown pores underneath.
Ganoderma lucidum produces a group of triterpenes, called ganoderic acids, which have a molecular structure similar to steroid hormones. It also contains other compounds many of which are typically found in fungal materials including polysaccharides such as beta-glucan, coumarin, mannitol, and alkaloids.