Northern Spy: An American apple native to the Northern East Coast discovered around 1800 in East Bloomfield, N.Y. Its name comes from the codename of an Underground Railroad operator, who guided former slaves through New England into Canada. Flavor is especially tart, and flesh is harder and crunchier than most, staying firm. Thin-skinned and aromatic, it is a consummate pie apple, and an old favorite for eating out of hand.

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