North America used to have a much more diverse assortment of apples. In fact, it's estimated that as many as 14,000 different varieties of apples were grown here in the 19th century. Today, only about 90 varieties are commercially grown.
From the Brooklyn Botanic Garden:
But in the 19th century, apples came in all shapes and guises, some with rough, sandpapery skin, others as misshapen as potatoes, and ranging from the size of a cherry to bigger than a grapefruit. Colors ran the entire spectrum with a wonderful impressionistic array of patterning—flushes, stripes, splashes, and dots. There was an apple for every community, taste, purpose, and season, with winter varieties especially prized. Apples were used for making cider, baking, drying, eating out of hand—even as livestock feed.
Compare all of this to the 90 or so varieties grown commercially in North America today, or to the handful of shiny cultivars on display at the local supermarket, and you are immediately faced with a pomological conundrum: How could Americans grow 14,000 different apples in the 19th century, and a hundred years later be conversant with only a few varieties, most notably, 'Red Delicious', 'Golden Delicious', and 'Granny Smith'?
You can read more about the history of apples and their "genetic fingerprinting" in the 2009 paper, Identification of Historic Apple Trees in the Southwestern United States and Implications for Conservation. [pdf]
Image: Actress Emma Haig biting into an apple via Getty