AppearanceThis polypore bears a marked resemblance to ''G. lucidum'' and generally has a stipe, sometimes lacking the characteristic red to purple varnished appearance that ''G. lucidum'' possesses. The flesh is spongy in pore tissue and firm in the stipe. The pores bruise brown when damaged.
Its habitat of choice is decaying stumps and roots of hardwoods, which aligns perfectly with that of ''G. sessile''.
EvolutionThe name was originally established by Miles Berkeley in 1849 as ''Polyporus curtisii'', and later transferred to the genus ''Ganoderma'' by William Alphonso Murrill in 1908. This species is tentative and is a subject of debate as to its viability as a distinct species from North American specimens described as ''G. lucidum'' , which is much more widely distributed throughout the US. There is also debate about the identities of several species that resemble ''G. lucidum'' and ''G. tsugae''.
One reason for an alleged synonymy between ''G. sessile'' and '' G. curtisii'' is overlap in habitat, decaying hardwoods. According to Volk, Gilbertson and Ryvarden, authors of ''North American Polypores'', it is not considered a separate species from ''G. lucidum''. Bessette et al., authors of ''Mushrooms of the Southeastern United States'', echo this and list it as a synonym to ''G. lucidum''. Paul Stamets considers ''G. lucidum'' and ''G. curtisii'' to both be members of a tight-knit species complex.
However, several recent molecular studies have shown ''Ganoderma curtisii'' to be genetically distinct from ''Ganoderma lucidum'', calling into doubt the synonymy of the two species and supporting previous mycologists' opinion that it is a distinct species. The same studies support the idea that ''G. lucidum'' sensu stricto is actually absent from the North American continent and that the mushroom widely called ''G.lucidum'' in North America is instead ''G.sessile'', a member of the ''Ganoderma resinaceum'' complex, with ''Ganoderma curtisii'' as a separate species.
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