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.
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.
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, hyperlipemia, 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.