Adventures in Ancient Plants

Patricia Gensel has spent her career studying 400-million-year-old plants at Carolina and across the globe.

Patricia Gensel
Patricia Gensel has worked at UNC-Chapel Hill for 49 years and is preparing to retire in Spring 2025 to work on her active research projects. (photo by Alyssa LaFaro)
June 18th, 2024

Upon first glance, the fourth floor of Wilson Hall on UNC-Chapel Hill’s campus is no different from the rest of the biology department building: fluorescent lighting, white tile floors, ancient wooden desks in professors’ offices.

But then Patricia Gensel leads me to a door at the end of the hallway. She buzzes with excitement as she slides the key into the lock. After a particularly satisfying “click,” the door opens — and her world unfolds. Floor-to-ceiling drawers filled with specimens. Rolling carts covered in rocks. And on a table in the center, a giant slab that most people can’t get their arms around.

“I don’t go in for small,” Gensel says with a laugh. “At one point I had about 4,000 specimens, but I donated a lot to museums in the U.S. and Canada. Now, I’d guess I have closer to 2,000.”

She directs my attention back to the giant rock. Upon closer inspection, an outline of what looks like some type of fern is embedded in its top.

“This is foliage. An early seed plant, most likely,” she says.

Gensel is a paleobotanist. She studies plants from the Devonian and Lower Carboniferous periods, which date back 327-400 million years — pre-dating dinosaurs. This timeframe marks the beginning of plants that lived on land, produced seeds, grew root systems, and developed wood, ultimately forming into trees.

“These are small, simple plants,” she explains. “Some of them lacked roots. Many of them lacked leaves. They mostly had a stem and a reproductive structure called the sporangium.”

Since joining the Carolina biology faculty in 1975, Gensel has drastically improved our understanding of these flora, uncovering new taxa — or classifications — of plants, approximating the number of species that existed, and rigorously documenting their evolution. To study them, she’s collected fossils found in rocks all over the world, from the Canadian arctic to Beijing to Australia, and has published this work in nearly 90 papers and a book.

She’s like Indiana Jones — but for plants.

Studying the history of plant life is key to understanding the planet’s development over time. They inform the biodiversity of the area they grew in and the animals that lived alongside them. Their various structures and lifecycles reflect Earth’s warming and cooling patterns — and can even indicate future pathways of our ever-changing climate.

“Plants give us oxygen, and without them, we wouldn’t be able to survive,” she says. “Plus, we all have an interest in knowing where we come from — and this is where we come from on a big scale.”

Snakes, spores, and schools

Gensel’s passion for plants stems from her childhood near Buffalo, New York, where she grew up tromping through her grandfather’s farm, mesmerized by the different organisms she was often surrounded by.

“He had a wooded area in the back of his farm, and in the spring, we would go and look at the wildflowers,” she recalls. “Also, my grandmother was interested in natural history. She was active in Audubon, and we’d look for birds together. It goes back a long way.”

This love for the natural world followed Gensel into her teens, and she spent her last two summers before college participating in summer science programs that included field trips to places like the Buffalo Museum of Science and the Adirondacks.

“I remember when this guy came in to talk to us about snakes — and brought one with him,” Gensel shares, chuckling. “It was great. I still love snakes and try to encourage people not to kill them when they see them.”

Majoring in biology was an easy choice for Gensel. About halfway through her undergraduate degree at Hope College in Holland, Michigan, she attended a lecture on fossil spores. And when she approached the professor to ask a few questions, he offered her a job in his lab.

“I think I always had an interest in plants, but this crystallized it,” she says.

Paleobotany was a way for Gensel to merge multiple interests. It requires foundational knowledge in both botany and geology, but also involves working at excavation sites, unearthing fossils with the same techniques archaeologists use to uncover artifacts.

While awaiting acceptance to graduate school, Gensel continued to work in the lab until her mentor introduced her to a palynologist — a person who studies fossil spores and pollen — who was looking for an assistant to aid him in his research on Devonian spores in London.

“I think it took me about two minutes to say yes,” Gensel says.

After a year, she realized she preferred studying whole plants versus spores and traveled back across the pond to work on master’s and PhD degrees at the University of Connecticut (UConn).

Patricia Gensel (center) and a group of researchers at a rock outcrop
rock with Devonian plant fossil on it
stone with a Lower Carboniferous fossil on it
a generated image of the Dr. Seuss tree
a rock with a Triassic fern fossil on it
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A pioneering paleobotanist

After graduating from UConn in 1972, Gensel stayed on as a postdoctoral researcher for a few years before landing a faculty position in the botany department at UNC-Chapel Hill in 1975. She and Ann Matthysse, also still at Carolina, were the first two female professors ever hired by the department.

Gensel continued to study plants from the Devonian period — a timeframe that had gaps in paleobotany literature. This meant Gensel had plenty of opportunity for discovery.

“This is a world where no flowering plants existed,” she says. “It’s a world where plants first became established in the land and diversified.”

To understand ancient plants, botanists must study how modern ones are constructed and function. Then, they trace those properties back in the timeline, searching for when they first appear and what caused their development. It’s incredibly challenging, Gensel admits, because these plants look drastically different from what we know today.

The first known land plants, called Cooksonia, were small and mossy with branches leading to tiny knobs. They lacked root structures, leaves, and wood — characteristics that wouldn’t show up until the Devonian period. Gensel was one of the first researchers to pinpoint when these traits appeared.

“I was fascinated by how many of these 400-million-year-old plants had features present in living ones,” Gensel shares. “At that time, they looked very different, but they still were doing some very similar things and were surprisingly more sophisticated than people thought when I first started out in this field.”

As Gensel added more and more data to the existing literature on Devonian plants, she began expanding her research into the next period in geologic history: the Lower Carboniferous — “Lower Carb” as Gensel calls it — about 327-359 million years ago. On average, scientists know less about this time because there are fewer places in the world where terrestrial sediment can be found. Two are on the East Coast: Virginia and New Brunswick, Canada.

Recently, Gensel has spent much time in New Brunswick alongside two colleagues who discovered one of the most intact fossilized trees from the Lower Carb to date. Contained in a rock about the size of a Mini Cooper, the tree they found has been preserved 3-dimensionally, which helped them reconstruct a model of what it would have looked like in its original form.

With its tall skinny trunk and almost equally long spindly leaves, the tree looks like something out of “The Lorax.” So, of course, the research team is affectionately calling it the “Dr. Seuss tree.”

“This tree is special because it doesn’t match any existing models we have of trees from this period,” Gensel explains. “It’s motivating me to further study the Lower Carb, comparing the different environments where the fossils can be found across Nova Scotia, Virginia, and Europe.”

An ending and a beginning

Gensel is one of just two botanists left at Carolina. During her 49-year career here, she watched the botany department dissolve into the biology department and the field shrink as biology students began to pursue more traditional fields of study like medicine and environmental science.

As she nears retirement in Spring 2025, she worries what will happen to her specialty as the years go on — especially since teaching, for her, has always been a place to share that passion and inspire the next generation of scientists to consider the field.

“Many of my students haven’t been exposed to this history, and they often tell me I open their mind to other ways of thinking,” Gensel says proudly. “I think it broadens their thinking about what we can learn from the past.”

For years, Gensel has brought classes to roadside outcrops in Pulaski, Virginia, for fossil hunting. She teaches them about different kinds of rock, how and where to search for fossils, and how to remove them intact.

“For students, this really makes fossils become real,” she says. “It’s an incredibly valuable experience.”

While retirement is in many ways an ending for Gensel, it’s also a beginning. Her time normally spent teaching will be fully devoted to her remaining research projects, of which she has many.

“I still find it exciting to work with these plant puzzles,” she says. “They’re some of the biggest and hardest puzzles out there.”

Patricia Gensel is a professor in the Department of Biology within the UNC College of Arts and Sciences. She is past president of the Botanical Society of America and a recipient of their Merit Award, Centennial Award, and the Palaeobotanical Award.