Thanks to the hard work of "apple detectives," five types of apples that once were thought to be extinct have been rediscovered in northern Idaho and eastern Washington state.

David Benscoter, a retired federal investigator, worked with Temperate Orchard Conservancy in Oregon and Fedco Seeds in Maine to get positive identifications on the fruit.

"I just love the history of these old apples and what they meant to the first homesteaders that arrived here in eastern Washington and northern Idaho," Benscoter told the Lewiston Tribune. "The apple was the most important fruit you could have, and it could be used in so many ways."

The rediscovered apples are the Shackleford, Saxon Priest, Kittageskee, Ewalt and McAffee varietals.

Apples can have as many as 50 different identifiers, including stem length, shape, size, color and the structure of the bottom.

A watercolor painting and cross section of a Shackleford apple
This 1912 watercolor depicts a Shackleford, a deep-red apple. (Photo: U.S. Department of Agriculture Pomological Watercolor Collection)

To help identify the apples, Benscoter used written descriptions from old books and antique watercolor paintings like the ones featured here.

The Shackleford apple, for example, is a large, deep-red apple that keeps well in storage. It's also consistent in shape, color and size, according to Benscoter.

A watercolor painting and cross section of a Hungarian Saxon Priest apple
This 1896 watercolor showcases a Saxon Priest Apple. This apple was one of many Hungarian varietals that were trialed at in the Washington State Experiment Station in 1896. (Photo: U.S. Department of Agriculture Pomological Watercolor Collection)

Benscoter first became interested in tracking down old and lost varieties of apples five years ago after he helped a neighbor with some yard work. The neighbor had an apple tree in her yard, and he began investigating.

"I got on the internet and was doing some research," he said. "It just kind of snowballed from there."

Sorting through old county fair records, Benscoter discovered several apples that were considered extinct. Since then, he has rediscovered more than 20 varieties that were considered lost.

A watercolor painting and cross section of an Ewalt apple
An Ewalt apple, depicted in this watercolor from 1905, was described as having a 'sprightly and pleasant' flavor in U.S. Senate documents from 1857. (Photo: U.S. Department of Agriculture Pomological Watercolor Collection)

Rediscovering these lost apples is important for genetic diversity in apples, according to experts at the Temperate Orchard Conservancy in Oregon.

"We need this diversity spread around," Joanie Cooper said to the Spokesman-Review. "Nobody knows for sure which apple is better."

The conservancy grafts scion wood onto root stock saplings to save those genes. Grafted trees will be available for sale starting in 2019, and the conservancy will also ship scion wood anywhere in the U.S.

A watercolor painting and cross section of a McAfee apple
A 1912 watercolor of a McAfee apple. (Photo: U.S. Department of Agriculture Pomological Watercolor Collection)

Benscoter estimates that of the more than 17,000 named apple varieties that originated in North America, only about 4,000 still exist today.

"Those apples have been forgotten about in the back of someone's field or an old orchard nobody has taken care of in a hundred years," Benscoter said. "I'm hopeful, and obviously the search has been somewhat successful, and so I think there are still many apples out there that can be found."

A watercolor painting and cross section of a Flushing Spitzenburg apple
The Flushing Spitzenburg, depicted in the 1899 watercolor, was described as 'moderately coarse, crisp' and 'not high in flavor' according to 'The Apples of New York,' published in 1905. (Photo: U.S. Department of Agriculture Pomological Watercolor Collection)

Benscoter also thinks he's found seven other apples that have not yet been confirmed or are extremely rare.

These include the Autumn Gray, Surprise No. 1, Flushing Spitzenburg (pictured above), Republican Pippin, Bogdanoff Glass, Flory and Early Colton.

Benscoter says the Early Colton is only the second one of its kind known to exist of antique age.