[chidg]

Mycologist here. Yes, they are different species. Your quote is partly correct in that 'magic truffles' (also known as philosopher's stones) are not real truffles. They are in fact sclerotia, a hardened 'resting stage' of the organism that protects against drought, and they are not a sexually reproductive part of the organism, unlike a true truffle or a mushroom. However it is incorrect in saying that apart from the visual appearance there is no difference, because there is a clear difference in biological function, and they are generally different species, at least as found in the commercial trade.

The species commonly sold and used as magic mushrooms (primarily Psilocybe cubensis) do not produce sclerotia. Conversely, the species that commonly produce sclerotia (Psilocybe mexicana amongst others - there's a lot of taxonomic uncertainty, partly because the mushrooms themselves are required for identification), although they can and do produce mushrooms, are never reported to be found being sold as mushrooms in commerce - only as sclerotia.

Further, there are consistently reported subjective differences in the experiences engendered by Psilocybe cubensis magic mushrooms and P. mexicana et al. sclerotia. Whether or not this is due to small differences in the profile of the various alkaloids, an as yet unidentified other psychoactive component, or simply psychological priming due to users being told they are different, we do not know.