Some books list this as Ganoderma lucidum, but the current best name for it is Ganoderma curtisii. Then again, it could be Ganoderma ravenelii, which "is nearly identical and grows on broadleaf trees or on the ground, but it has a creamy white to buff flesh that lacks black, shiny, resinous deposits" (Polypores and Similar Fungi of Eastern and Central North America, p. 146).
I found this growing at the base of a half-dead Shingle Oak (Quercus imbricaria). It is a tough, corky mushroom with a varnished cap and stem. The pore surface is yellow-white and readily bruises brown. In Mushrooms Demystified, this mushroom keys out easily: The pore surface is not rosy; the cap and stem appear varnished; it grows on hardwood; and the cap is "ochre to whitish or only partly red" (p. 574). This one's cap was a lovely pale yellow.
Ganoderma means "shiny skin" and the species name honors Moses Ashley Curtis. This mushroom is closely related to the east Asian Ganoderma lingzhi. Lingzhi means "tree of life mushroom." In Japan, it is known as Reishi, "divine mushroom." Ganoderma lucidum applies to the European version.
Finding this mushroom gives me a special thrill that's nearly unrivaled. This mushroom simply has an aura about it. It is a mushroom I respect.
It's also a case study in complexity, misinformation, and the value of being pragmatic and recognizing that human knowledge is necessarily limited and fallible. Anyone wishing to learn more about this mushroom should read the sections on this mushroom in Paul Stamets' Growing Gourmet and Medicinal Mushrooms and Mycellium Running and Appendix D: "The Medicinal Uses of Polypores" in Bessette's Polypores and Similar Fungi of Eastern and Central North America.
The taxonomy of this mushroom is far from cut and dried, so it's better to think of this as a species complex. Further, ecology, not just morphology, is a factor in its identity. This in turn feeds into the complexity pertaining to its medicinal use--there have been many over-blown claims regarding its healing powers, but that fact should not be taken as a wholesale dismissal of its powers.
For me, this mushroom can be polarizing: it can set the rigorous, skeptical, scientific mind against the naive, uncritical mind that is always looking for the next panacea. Both perspectives can justifiable scoff at the other. But I wish to avoid as much as I can dichotomies that create enemies. I like to listen to Pink Floyd's "Us and Them."
So what's the alternative? For me, it's a couple core tenets from Buddhist philosophy: (1) names are provisional expedients and (2) dependent origination rather than transcendental, immutable essence is the best way to understand identity: As the Buddha says, "this is because that is; this is not because that is not; this ceases to be because that ceases to be."
I call this mushroom Ganoderma curtisii, but I also call it Lingzhi, but I come closer when I call it that lovely wonder, that majestic portion of the time-being I found walking with my son by an old cemetery near Carlyle Lake.
There is nothing to eat,
seek it where you will,
but the body of the Lord.
The blessed plants
and the sea, yield it
to the imagination
--William Carlos Williams, "The Host"