Ganoderma lucidum

''Ganoderma lucidum'' is a red-colored species of ''Ganoderma'' with a limited distribution in Europe and parts of China, where it grows on decaying hardwood trees. Wild populations have been found in the United States in California and Utah, but were likely introduced anthropogenically and naturalized.

Etymology

The scientific name, ''Ganoderma lucidum'', uses the genus name, ''Ganoderma'' (derived from the Greek ganos/γάνος "brightness, sheen", hence "shining" and derma/δέρμα "skin") combined with ''lucidum'' from Latin for "lucidus" as light, bright or clear.

Taxonomy and history

The history of the ''Ganoderma lucidum'' taxon is tied to the history of ''Ganoderma'' as a genus. Karsten first described the ''Ganoderma'' in 1881 and included only one species in the genus, ''G. lucidum'' (Curtis) Karst. Previously, it was called ''Boletus lucidus'' Curtis (1781) and then ''Polyporus lucidus'' (Curtis) Fr. (1821). Patouillard revised Karsten's genus Ganoderma to include all species with pigmented spores, adhering tubes and laccate-crusted cuticles, which resulted in a total of 48 species classified under the genus ''Ganoderma'' in his 1889 monograph.

Despite this recognition of additional species and subsequent discoveries of new ''Ganoderma'' species, such as 17 new North American species identified by Murrill North in 1902, the taxonomy of Ganoderma species has remained chaotic, and the species name ''Ganoderma lucidum'' continues to be used for most ''Ganoderma'' species, including commonly misidentifying '' Ganoderma lingzhi'' (also known as reishi mushroom (Japan) or lingzhi/ling chih (China)), the sought-after red ''Ganoderma'' species used in traditional Asian medicine. It is important to note that ''G. lucidum'' is not a synonym for ''G. lingzhi'' and is not in the same clade: based on molecular phylogenetic analyses, ''G. lucidum'' is more closely related to North American species '' Ganoderma tsugae'' and '' Ganoderma oregonense'' than to ''G. lingzhi'', whose sister taxa include '' Ganoderma curtisii'' and '' Ganoderma ravenelii''.

These genetic analyses tested species concept hypotheses to determine how the ''Ganoderma'' taxa are related. One such study found six major clades among the 29 samples studied. Samples labeled as ''G. lucidum'' were found in five of the six clades, showing the extent of the confusion around species identification. Another study found similar results, and also showed that '' Ganoderma resinaceum'' from Europe and the North American sample wrongly labeled ''G. lucidum'' were sister taxa and were also more closely related to each other than the European ''G. lucidum'' sensu stricto. A recent multilocus phylogeny, using ITS, tef, rpb1, and rpb2, revealed that the global diversity of the ''Ganoderma'' species included three supported major lineages. These results agree with several of the earlier works focusing mostly on morphology, geography and host preference, but with statistical support separating the European and North American taxa. The phylogenetic species concept using a multilocus approach is currently the most robust and accepted method for designating species ranks for the fungi.

Description

''Ganoderma lucidum'' has a limited distribution in Europe and parts of China, where it grows on decaying hardwood trees.

The fruiting body almost always has a stipe present, which is tawny to russet colored and 1.5 times the diameter of the cap. Context tissue (sterile tissue inside the fruiting body between the pileus crust and the initiation of the tubes) is pink-buff to cinnamon-buff and corky, showing concentric growth zones and no resinous or melanoid deposits. The hymenium displays 4–5 pores per millimetre. Chlamydospores are absent. Basidiospores are 8.2–12.1 μm (average 10.7 μm) long and 4.8–8.9 μm (average 7.1 μm) wide, with a spore shape index of 66.2.

Uses

The species is inedible but is used to make a bitter-tasting tea.

Folklore products and tissue culture samples

The confusion surrounding the taxonomy of ''Ganoderma'' species has persisted, causing confusion and inaccuracies when labeling folklore products containing ''Ganoderma'' species, as well as "grow your own" (GYO) kits and other tissue samples sold for cultivation of ''Ganoderma'' species. Products typically carry a label of ''G. lucidum'', using the words "reishi" and "lingzhi/ling chih" (which most typically refer to Asian ''Ganoderma'' species used in traditional medicine, such as ''G. lingzhi'' and ''Ganoderma sinense'') merely because they contain a laccate ''Ganoderma'' species.

These products and GYO kits sold as ''Ganoderma lucidum'' may not contain ''G. lucidum'': one study showed through DNA analysis that 93% of GYO kits and half of the dried mushroom products studied that were labeled "''G. lucidum''" contained ''G. lingzhi'' in actuality, an inaccurate labeling. The study also found that no manufactured reishi product and only one GYO kit actually contained ''G. lucidum''. Other species present in these products included '' Ganoderma applanatum'', ''Ganoderma australe'' (potentially a species complex), ''Ganoderma gibbosum'', ''Ganoderma sessile'', and ''G. sinense''.

References

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Ganodermataceae
Inedible fungi
Taxa named by Petter Adolf Karsten