Mandragora, mandrake, man-dragon?

According to Wiktionary, one definition of mandrake or mandragora is "a kind of tiny dragon immune to fire." Ostensibly this is because mandrake may be falsely analyzed as a compound of man and drake. Wiktionary provides no source for this definition so I used Google Books to find where this etymology came from...

...and I was unable to find any one source that corroborates Wiktionary's assertion and I suspect it may be due to a contributor mistake. However, I did find some sources that may have predicted this folk etymology:

• The New International Encyclopædia, Volume 14 states that the word mandrake was "influenced by popular etymology with man + drake, dragon, in allusion to the shape of the root and its supposed aphrodisiac qualities." In other words, the horndog plant.
• Missouri Botanical Garden Bulletin, Volumes 13-14 mentions "the interesting etymological change from the classical "mandragora" to the English mandrake, meaning "man-dragon", analogous to the French "main-de-gloire." Logic gave to the female mandragora the name "womandrake" or "Woman-dragon."
• Adventures in Unhistory by Avram Davidson includes an interesting article (originally from Isaac Asimov's Science Fiction Magazine - Volume 6) starting on page 67 which speculates on the etymology of mandrake and briefly analyzes it as a compound of man and dragon, "man-dragon" or "man-snake", before discarding that etymology as false.

So others have analyzed this same folk etymology at least as far back as a century ago. The Wiktionary definition actually varies in the two places it appears and disagrees whether the mandrake is a tiny dragon or a tiny demon. There are existing words for these concepts: dragonet meaning tiny dragon and imp meaning tiny demon. Neither of these claim immunity to fire, so I personally suspect the author confused the mandrake with the mythical salamander because of the shared /mandr/ pronunciation. The mythical salamander was immune to fire and could easily have been mistaken for a tiny dragon, so that is probably where the confusion comes from.

Real language drifts in meaning over time, so I see nothing wrong with mandrake gaining additional meanings as a synonym for dragonet, imp, and salamander.

Addendum 12/15/2020: It turns out that the source is An Encyclopaedia of Occultism by Lewis Spence.