The lingzhi mushroom or reishi mushroom encompasses several fungal species of the genus Ganoderma

Ganoderma

Ganoderma is a genus of polypore mushrooms which grow on wood and include about 80 species, many from tropical regions. Because of their extensive use in traditional Asian medicines, and their potential in bioremediation, they are a very important genus economically. Ganoderma can be differentiated...

, and most commonly refers to the closely related species, Ganoderma lucidum and Ganoderma tsugae

Ganoderma tsugae

Ganoderma tsugae, also known as Hemlock varnish shelf, is a flat polypore mushroom of the genus Ganoderma. In contrast to Ganoderma lucidum, to which it is closely related and which it closely resembles, G. tsugae tends to grow on conifers, especially hemlocks. Like G. lucidum, G. tsugae is said to...

. G. lucidum enjoys special veneration in East Asia

East Asia

East Asia or Eastern Asia is a subregion of Asia that can be defined in either geographical or cultural terms...

, where it has been used as a medicinal mushroom in traditional Chinese medicine

Traditional Chinese medicine

Traditional Chinese Medicine refers to a broad range of medicine practices sharing common theoretical concepts which have been developed in China and are based on a tradition of more than 2,000 years, including various forms of herbal medicine, acupuncture, massage , exercise , and dietary therapy...

 for more than 2,000 years, making it one of the oldest mushrooms known to have been used medicinally.