I agree (at least partially) with copperbadge that magical realism is fantasy without world-building. I'm not sure that the fantasy elements need to be symbolic, I think they can be included for the pleasure of strangeness.
However, in magical realism, the fantastic element might be at a realistic scale. If the authorial voice is getting extreme about the effect of the mermaid's beauty filling city districts and her tail walloping everything from sharks to sperm whales, we might be in tall tale country.
However, there's more to tall tales than exaggeration-- it isn't a straightforward grab at the emotions, it's taking pleasure in how wild the description can get.
So far, my list of tall tale fiction includes Lafferty, Esquivel's Like Water for Chocolate, and Helprin's A Winter's Tale. Any other suggestions?
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