When John Bunker first moved to Palermo 50 years ago, he was struck by the lack of street name signs in town.

“None of the roads had (name) signs, because after all, everybody knew what all the roads were,” said Bunker, Maine’s foremost apple historian, who also runs the orchard at Palermo’s Super Chilly Farm. “So I didn’t even know what road I lived on.”

Compounding the confusion, he recalled, was that segments of the same road sometimes had different names.

Palermo’s lack of formal street-naming conventions was interesting and a little confusing, but not alien to Bunker. Because before the 20th century, important information about each particular apple variety was often passed along by oral tradition. Unique varieties migrated from region to region along with the people who cherished those particular apples, sometimes getting renamed along the way without any documenting of the change.

“Those apples were like folks songs that traveled around and had different lyrics in different states,” Bunker said.

Some apple trees planted in Maine since the end of the Civil War – and throughout the country –  are in fact well documented with names and descriptions of their phenotypes, or observable characteristics. But for most of what we now call heirloom apples, “descriptions are either nonexistent or…