Varnish Shelf – Ganoderma tsugae


Ganoderma tsugae growing on the many dead hemlock trees in Shenandoah National Park


Common Name: Varnish shelf, Hemlock polypore, Ling zhi or ling chi (Chinese), Reishi (Japanese) – The laccate upper surface of the pileus (cap) has the sheen of varnished wood; its lateral single point attachment juts from the tree bole like a shelf.

Scientific Name: Ganoderma tsugae – The generic name is a combination of the Greek ganos, meaning ‘brightness’ and derma, meaning ‘skin’ in reference to the glinting surface, or skin, of the fungus. The genus of hemlock trees is Tsuga; the fungus is most frequently found on a hemlock host. Ganoderma lucidum is essentially identical in appearance and grows on deciduous trees; lucidum is Latin for ‘full of light, clear, bright’ – an additional reference to the lacquered semi-circular cap, or basidiocarp.

Potpourri:  The iridescent glow of this burnt orange bracket fungus evokes a numinous provenance that distinguishes it from its more mundane polypore cousins. It undoubtedly caught the eye of the earliest hominids who may have originally used it as an adornment to their environs; it is collected to this day for its natural beauty. Its mystical appearance as an excrescence on a tree bole prior to the advent of the understanding of the scientific age may also have led to its association with local divinities, a sylvan gift from the gods. It is too tough to eat, but it can be readily ground up for consumption; it has been in use in China as a medicinal tea for millennia. It was listed in Shen Nong Ben Cao Jing, which is one of the earliest Chinese herbal texts, and dates to the Eastern Han Dynasty (25 – 220 CE). Paul Stamets in Mycelium Running notes that “the earliest mention of ling chi occurred in the era of the first emperor of China, Shih-huang of the Ch’in Dynasty (221 – 207 BCE).”

Ganoderma is “probably the most morphologically complex genus of polypores” according to Chang and Miles in Mushrooms: Cultivation, Nutritional Value, Medicinal Effect and Environmental Impact. Over 250 separate species have been identified; the taxonomy is based on significant variability in both microscopic and macroscopic physical characteristics. The proliferation of names is attributable at least in part to the global geographical distribution of the fungus and to its extensive use as an herbal medicine. The advent of DNA analyses has resulted in a significant reorganization of the original fungal taxonomy of Linnaeus. A phylogenetic study of the Ganoderma genus based on mitochondrial DNA published in the publication Mycologia in 2004 found that the 250+ species were in actuality only 6 monophyletic (from a single parent) groups. It is notable that strains of G. tsugae and G. lucidum from both North America and Europe were found to be in the same grouping. However, strains of G. lucidum from Korea and Japan were identical to each other, but different from the strains of G. lucidum from Europe and North America. The study concluded that “G. lucidum, the most cosmopolitan member of the Ganoderma, was polyphyletic according to geographical origins.” This may have some significant implications for the burgeoning market for Ganoderma products. A study conducted by the Taiwanese Biotechnology Research and Development Institute in 2002 found that Ganoderma products were the highest volume product in their health food market and that the most widely used raw material was G. tsugae. The estimated annual production of the more reliable Asian G. lucidum was 4300 Metric Tons (MT) in 1997 (3000 MT in China alone) with a market value of about $1.6B.

Ganoderma lucidum grows on deciduous trees

One of the primary defining taxonomic aspects of the Ganoderma genus is the presence of thick double-walled spores called chlamydospores (chlamys is Greek for ‘mantle’ – a protective cover). These spores are highly protective against environmental extremes and help explain the global proliferation of the fungal genus. Ganoderma fungi, once grown from the chlamydospores, consist of corky, thick fruiting bodies that grow on hardwoods or conifers according to the species; they are in all cases a white rot, wood decay saprobe. A saprobe derives its nutrition from dead plants – fungi that live on live plants are parasitic or mycorrhizal. This is not to say that they are benign, as they can also infect live trees. According to Bryce Kendrick in The Fifth Kingdom “Ganoderma may not kill trees, but they cause serious decays of both standing and structural timber. These rots cost us many millions of dollars every year.” There are white rot fungi and brown rot fungi; the color distinction refers to what they don’t consume rather than what they do. In other words, white rot fungi consume the brown lignin (and some but not all of the white cellulose) so that the resultant decayed mass is white in color. Conversely, brown rot fungi consume only the white cellulose so the end result is brown.


The use of G. lucidum and G. tsugae in China from the dawn of prehistory with purported benefits to health, life and longevity has resulted in the attribution of preternatural powers to the fungi. The word ‘ling’ in Chinese translates into something like ‘spiritual, miraculous, and/or divine’ and conveys a notion of its efficacy and provenance. This has been exaggerated in the English rendition to everything from ‘mushroom of immortality’ to ‘magic fungus.’ From China, the beneficence of Ganoderma spread to the rest of Asia; in Japan, it is called either reishi, which means something like ‘auspicious plant’ or ‘immortality plant,’ or mannentake, which translates to ’10,000 year mushroom’ The extensive history of the use of Ganoderma as part of a long-term health regimen and the vast body of fervent, though hearsay, testimonials by its users establishes at least the likelihood of a modicum of truth to its purported life extending properties.

Assays of G. lucidum and G. tsugae over the past half century have revealed that they contain a virtual pharmacological cornucopia of potentially beneficial chemical compounds. Over 150 triterpenes and 50 polysaccharides have been identified as being uniquely derived from this fungal group starting from the first isolation of Ganoderic acids A and B in 1984 (these numbers vary according to the source – Stamets lists 119 triterpenes and 100 polysaccharides in Mycelium Running). Triterpenes are precursors to steroids in both plants and animals and very generally have cytotoxic (cell killing), liver protecting and lipid lowering effects. Polysaccharides are much more generic, consisting of long chains of carbohydrate molecules such as cellulose and chitin. In the case of the Ganoderma fungi, the polysaccharides are found to be carcinostatic; they inhibit the growth of cancerous tumors. Laboratory studies of the compounds that can be derived from Ganoderma fungi and their effects on a wide-range of medical problems are legion and on-going. Anti-tumor behavior has been demonstrated in ganoderic acids T, V, W, X, Y and Z, a property that is attributed to the stimulation of the body’s own production of lymphocytes as opposed to a direct effect. Ganodermic acid S inhibits the aggregation of platelets and could thus be beneficial in as an anti-clotting agent to prevent embolism-induced strokes. In what may also be related to coagulation, Ganoderma acid F acts to lower blood pressure. Several derivatives including Ganoderic acids R and S and Ganosporeric acid A have been shown to improve liver function, a finding that supports the traditional Chinese use of G. lucidum to treat hepatitis.

According to Chang and Miles in Mushroom, Ganoderma fungi were used in traditional Chinese medicine “to improve intellectual capacity and memory, to promote agility, to lengthen life span, and to relieve hepatopathy, nephritis, hyperglycemia, arthritis, asthma, gastric ulcer, arteriosclerosis, leukemia, diabetes and anorexia.” The ‘mushroom of immortality’ may in some ways be true to its metaphor in promoting longevity, lending credence to (mostly Asian) health regimen of daily Ganoderma tea to offset the ravages of time and age. While there is certainly nothing inimical to this practice, a cautionary note is proffered: there is at this juncture a great deal of uncertainty concerning geographic origin and species. In addition, the chemical complexity of the various Ganoderma species is daunting and therefore attributing syllogistic relations to a specific disease is at this point dubious. An elixir perhaps, but a medicine no.