Imprint on History

Escaping the torture of the whip and chain, hundreds of former slaves trickled into Roanoke Island, N.C. It was 1862, Union troops were invading the South, and slaves found safety from the Confederates—and their former masters—in this military outpost. These ragged men, women and children created a thriving colony with homes, a school and churches.

But two years later, their community was thrown into chaos when the Union Army abruptly conscripted all the men—young, old or disabled—sending them nearly 200 miles away from their families. Their job: to dig a 500-foot-long canal out of clay-heavy soil.

They were promised pay and rations that never appeared. Their pleas to military leaders were ignored. And when the war ended and they were released from their forced labor, their story was forgotten.

Nearly 150 years later, UMD graduate student Nathan Jud stumbled upon a dime-size leaf fossil, uncovered in the earth those men exposed. He’s brought their story to light—and is also using that plant to change our understanding of one of the longstanding conundrums of evolution.

Two decades after Charles Darwin published “The Origin of Species,” one major problem still confounded him: the relatively sudden appearance of angiosperms, or flowering plants, in the fossil record and their near-complete takeover of the planet. Writing to a friend, he called it an “abominable mystery,” and it has remained so.

This was the problem Jud sought to tackle in his work toward a doctorate in biological sciences.

Flowering plants first appeared in the fossil record 130 million years ago, but plants have existed on Earth for 400 million years. “It’s like they showed up in the fourth quarter and dominated the game,” he says.

While dinosaur and human fossils get most of the attention, plant fossils could help scientists refine their views of how life on earth evolved.

“We should care more about plants than we do,” says Charles Delwiche, a member of Jud’s dissertation committee. He’s also a professor of cell biology and molecular genetics who studies the early evolution of photosynthetic life. “These organisms profoundly affect every aspect of our daily lives.”

“Everything we eat is either a plant product or an animal that ate plants—or an animal that ate animals that ate plants,” he says. “All of our clothing is either a plant product or made from fossil fuels, which were either plants or algae. The vast majority of the energy industry is dependent on plant products. We have oxygen in the atmosphere because of the activities of plants and algae.”

The proliferation of flowering plants doesn’t follow the spread of other species throughout Earth’s history. At least five times since our planet’s formation, mass extinctions have created a space for new species to fill, giving rise to the age of dinosaurs, and most recently, mammals. Flowering plants didn’t have the advantage of a mass die-off.

Unraveling the mystery of angiosperms—identifying the characteristics that helped them adapt and the environments in which they thrived—could advance scientists’ knowledge of climate change, conservation, biodiversity and our own evolution.

“You can’t understand how life on earth got to be the way it is without understanding the history of the flowering plant,” says entomology Professor Charles Mitter, Jud’s UMD co-adviser, who studies the co-evolution of flowering plants and insects.

Jud is the first student in UMD’s Graduate Program in Behavior, Ecology, Evolution, and Systematics to be jointly advised by a scientist from the National Museum of Natural History. He was given full access to the Smithsonian’s resources, was awarded funding through the museum’s predoctoral fellowship program and participated in excavation trips with its researchers.

Jud’s tiny leaf, so modern and complex, has all the markings of a eudicot and indicates that flowering plants evolved quickly by geological standards. He compared the fossil to living plants on the evolutionary tree, citing features such as “teeth” at the tips of the leaves and interlocking “veins” within the leaves. He went on to create a list of 14 characteristics that can now be used to distinguish the leaves of flowering plants from those of non-flowering plants. (In the past, fossils like this one were often mistaken for small ferns.)

“It’s a new Rosetta Stone” for paleobotanists, says Scott Wing, Jud’s Smithsonian co-adviser and curator of fossil plants at the National Museum of Natural History. “We have a new tool to recognize this group very early in its evolution.”

The fossil was among hundreds gathered in the 1970s by Leo Hickey, a leading paleobotanist who worked at the Smithsonian Institution and Yale University, and his colleagues. It came from Dutch Gap, an area just south of Richmond, Va., which contains the oldest known fossils of flowering plants in North America, dating back 120 million years.

Jud, like all scientists who discover a new species, had the privilege of naming it.

He set out to learn more, scouring the Internet until he found Steven Miller, co-editor of the Freedmen and Southern Society Project—right in Maryland’s Department of History.

To be a freedman during the Civil War often meant trading one master for another. After a few early incidents in which Union soldiers returned slaves to their owners, the military soon realized it could bolster its ranks with the mounting numbers of escaped slaves.

In the summer of 1862, President Abraham Lincoln started circulating a draft of the Emancipation Proclamation, and though it wasn’t made official until Jan. 1, 1863, the Union Army started accepting black men. Women and children, and men who weren’t fit to serve, were sent to “contraband camps,” similar to refugee camps, to wait out the war.

In 1864, at least 45 black men—many of whom already worked without pay on fortifications for the army—were tricked into leaving their families with promises of $16 a month and rations.

“Every time the Union or the Confederate army needed hard work done, they would try to find black men to do it,” Miller says.

Union Gen. Benjamin Butler wanted to circumvent the Confederate Army stationed along an eight-mile stretch up the James River that Union ships had to pass to reach the heart of Virginia. At Dutch Gap, only 500 feet separated one curve of the river from the next, making it a perfect place for a canal.

Black soldiers did the digging at first, but as the project continued, more workers were needed—and the men of Roanoke Island were easy targets.

Miller obtained from the National Archives a firsthand account of their “recruitment,” written by Ned Baxter and Sam Owens on behalf of 43 other men, in a letter to Butler, reproduced with its original spelling and punctuation:

When they arrived at Dutch Gap, they faced a gargantuan task: shoveling out 67,000 cubic yards of soil, or the volume of more than 20 Olympic-size swimming pools.

The black soldiers who worked on it were on the military payroll, at least, despite rampant discrimination. The freedmen could only hope their letter reached the right place and that the military would act honorably.

It was a virtual return to slavery for six months—until Butler was relieved of his duties in January 1865 and the project was abandoned. The war ended a few months later, and it wasn’t until he became a U.S. senator in the 1870s that Butler oversaw the canal’s completion.

That’s the Greek name Jud chose for the new species.

The first part is straightforward: Potomac, for the area where the fossil was collected, and “kapnos,” which means smoke, to connect it to the plant’s modern-day counterparts, like fumitories, with similar scientific names.

The second part, apeleutheron, means “freedmen’s.”

It honors all the freedmen who made it possible for Jud to challenge long-held assumptions about the earliest flowering plants in North America.

Jud and Hickey wrote a paper that was published in December in the American Journal of Botany. As scientists continue to refine their understanding of the evolution of flowering plants, Jud hopes they’ll spare a thought for the men who inadvertently made their work possible.

“This fossil belongs to the freedmen,” Jud says. “I want to bring light to a little bit of history, dug out from obscurity.” TERP

Sometimes, paleobotanists need only a glance to determine whether a fossil is a fern or a flowering plant. But when it gets trickier, especially in the earliest flowering plants, Jud’s new research offers key features to tell them apart.

The best way for a layman to tell is by the organization of veins in the leaf. In a fern, they usually come straight out from the middle of the leaf and run parallel to each other. But sometimes, ferns can have more interlaced veins, which can be checkerboard-like in their regularity (the checkerboard decreases in size as it reaches the outer edges of the leaf). In a flowering plant, the veins always interlock, and there can be many veins of varying thicknesses that form irregular shapes.

Jud’s notes throughout the quiz will help explain why each fossil is a fern or a flowering plant.

Ready to test your skills? Good luck!