Over at Mother Jones, here's Rowan Jacobsen's story about one man's quest to bring hundreds more back:
The key thing to understand about apple varieties is that apples do not come true from seed. An apple fruit is a disposable womb of the mother tree, but the seeds it encloses are new individuals, each containing a unique combination of genes from the mother tree and the mystery dad, whose contribution arrived in a pollen packet inadvertently carried by a springtime bee. If that seed grows into a tree, its apples will not resemble its parents'. Often they will be sour little green things, because qualities like bigness, redness, and sweetness require very unusual alignments of genes that may not recur by chance. Such seedling trees line the dirt roads and cellar holes of rural America.
If you like the apples made by a particular tree, and you want to make more trees just like it, you have to clone it: Snip off a shoot from the original tree, graft it onto a living rootstock, and let it grow. This is how apple varieties come into existence. Every McIntosh is a graft of the original tree that John McIntosh discovered on his Ontario farm in 1811, or a graft of a graft. Every Granny Smith stems from the chance seedling spotted by Maria Ann Smith in her Australian compost pile in the mid-1800s.
[Photo Credit: Séan Alonzo Harris]