Ganoderma lucidum, commonly known as thereishi,varnished conk, orling chih,^[2] is a red-colored species ofGanoderma with a limited distribution in Europe and parts of China, where it grows on decaying hardwood trees.^[3] Wild populations have been found in the United States in California and Utah but were likely introduced anthropogenically and naturalized.^[1]

Ganoderma lucidum
Ganoderma growing under oak in California[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Fungi
Division:	Basidiomycota
Class:	Agaricomycetes
Order:	Polyporales
Family:	Ganodermataceae
Genus:	Ganoderma
Species:	G. lucidum
Binomial name
Ganoderma lucidum Karst (1881)
Synonyms
Boletus lucidus(Curtis)Polyporus lucidus(Murrill)

Ganoderma lucidum Mycological characteristics
	Pores onhymenium
	No distinctcap oroffset
	Hymenium attachment is irregular or not applicable
	Stipe isbare or lacks astipe
	Spore print isbrown
	Ecology isparasitic
	Edibility is edible, butunpalatable

The history of theGanoderma lucidum taxon is tied tothe history ofGanoderma as a genus. Karsten first described theGanoderma in 1881 and included only one species in the genus,G. lucidum (Curtis) Karst.^[4] Previously, it was calledBoletus lucidus Curtis (1781) and thenPolyporus lucidus (Curtis) Fr. (1821).^[4] Patouillard revised Karsten's genus Ganoderma to include all species with pigmented spores, adhering tubes andlaccate-crustedcuticles, which resulted in a total of 48 species classified under the genusGanoderma in his 1889 monograph.^[5][6]

Despite this recognition of additional species and subsequent discoveries of newGanoderma species, such as 17 new North American species identified by Murrill North in 1902,^[5][7] the taxonomy of Ganoderma species has remained chaotic, and the species nameGanoderma lucidum continues to be used for mostGanoderma species, including commonly misidentifyingGanoderma sichuanense (=Ganoderma lingzhi) (also known as reishi mushroom (Japan) or lingzhi/ling chih (China)), the sought-after redGanoderma species used in traditional Asian medicine.^[3] It is important to note thatG. lucidum isnot a synonym forG. sichuanense (norG. lingzhi) and is not in the same clade: based on molecular phylogenetic analyses,G. lucidum is more closely related to North American speciesGanoderma tsugae andGanoderma oregonense than toG. sichuanense, whose sister taxa includeGanoderma curtisii andGanoderma ravenelii.^[1]

These genetic analyses tested species concept hypotheses to determine how theGanoderma taxa are related. One such study^[8] found six major clades among the 29 samples studied. Samples labeled asG. lucidum were found in five of the six clades, showing the extent of the confusion around species identification. Another study^[9] found similar results, and also showed thatGanoderma resinaceum from Europe and the North American sample wrongly labeledG. lucidum were sister taxa and were also more closely related to each other than the EuropeanG. lucidum.

A 2015phylogeny study revealed that the global diversity of theGanoderma species included three supported major lineages.^[10] These results agree with several of the earlier works focusing mostly on morphology, geography and host preference, but with evidence separating the European and North American taxa.^[11]

The scientific name,Ganoderma lucidum, uses the genus name,Ganoderma (derived from Greek ganos/γάνος 'brightness, sheen', hence 'shining' and derma/δέρμα 'skin') combined withlucidum fromLatinlucidus 'light, bright, clear'.^[12]

Thefruiting body almost always has astipe 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.^{[citation needed]} 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.^[1]

G. lucidum is widely distributed in tropical and subtropical rainforest regions inAsia,Africa, andAmerica.^[3][13][14] It has been used for the longest time inChina,Vietnam, andIndia.^[15][16] It is currently cultivated using intensive cultivation technology inJapan,Korea,China, and is starting to be cultivated in someSoutheast Asian andSouth American countries.^[17][18] In the southern region ofVietnam,G. lucidum can be seen growing on dầu lim trees onPhu Quoc Island.^[19][20][21]

The species is inedible, and rock-hard when dried, but is used to make a bitter-tasting tea, purported to have health effects by some cultures, although there is no reliable scientific evidence for such effects.^[22]

The confusion surrounding the taxonomy ofGanoderma species has persisted, causing confusion and inaccuracies when labelingfolklore products containingGanoderma species, as well as "grow your own" (GYO) kits and other tissue samples sold for cultivation ofGanoderma species.^[1] Products typically carry a label ofG. lucidum, using the words "reishi" and "lingzhi/ling chih" (which most typically refer to AsianGanoderma species used in traditional medicine, such asG. sichuanense andGanoderma sinense) merely because they contain a laccateGanoderma species.^[1]

These products and GYO kits sold asGanoderma lucidum may not containG. lucidum: one study showed throughDNA analysis that 93% of GYO kits and half of the dried mushroom products studied that were labeled "G. lucidum" containedG. sichuanense in actuality,^[3] an inaccurate labeling. The study also found that no manufactured reishi product and only one GYO kit actually containedG. lucidum. Other species present in these products includedGanoderma applanatum,Ganoderma australe (potentially aspecies complex),Ganoderma gibbosum,Ganoderma sessile, andG. sinense.

^[3]

Due to its medicinal properties and other mentioned benefits, the cultivation ofGanoderma lucidum is currently under study in Europe, although it remains in the early stages. Current research aims to cultivate it in different types of side-streams and waste,^[23][24] but this species are not usually cultivated in pine wood as it does not usually produce fruiting bodies as well as in other woods, such as aspen probably because softwoods contain compounds which are toxic to several fungi, includingGanoderma spp.^[25] However, recent studies found thatGanoderma lucidum is still able to degradePinus sylvestris wood, causing a wood delignification but keeping proportion of carbohydrates high,^[26] opening new doors to softwoods in their utilization inGanoderma lucidum cultivation.

Garnoderma lucidiums active components includeGanoderic acid, alkaloids, flavonoids and saponin which is used for antimicrobial and anti Malaria treatment^{[citation needed]}