When senior Matt Leopold goes on a hike these days, he can’t move very fast.
“I’d be way behind, because I just kept taking photos of the ferns,” Leopold said.
Stopping for ferns is an occupational hazard that he has fully embraced. Leopold, a molecular biology major, has spent the last two years in the Watkins Lab under the supervision of Professor of Biology Eddie Watkins, studying the physiology of wood ferns in the dryopteris genus. His senior thesis, “Seasonal Shifts in the Physiology of Wood Ferns,” zeroes in on a question that sounds simple but turns out to be surprisingly rich: how do ferns with different numbers of chromosomes behave differently across a growing season? The answer, Leopold believes, has implications that stretch far beyond the forest floor.
The three species at the center of Leopold’s research are Dryopteris intermedia — a diploid with two complete sets of chromosomes — plus Dryopteris cristata — a tetraploid with four — and also Dryopteris xbootii — a sterile triploid hybrid of the two.
Triploids are situated at a fascinating genetic crossroads, Leopold explained. They carry genetic material from both of their parents, and might theoretically benefit from hybrid vigor — the phenomenon in which hybrids outperform their parents in stress tolerance, growth rate and fitness.
“Polyploidy is when you have more than two complete sets of chromosomes, so there’s extra raw genetic material that you can choose from that might be advantageous,” Leopold said. “I’m trying to see if the triploid has advantages that hybridization can bring.”
Previous research by Watkins and collaborators found that triploid ferns generally exhibited intermediate traits between its diploid and tetraploid parents. But that study only captured a single snapshot in time. Leopold’s thesis extends the inquiry across an entire growing season — he took measurements in early June, late June and then September — to see whether that intermediacy changes as conditions do. His work proposes a genuine contribution to the field, as there exists limited research about the seasonal physiology of ferns, and even less work that compares the physiology of ferns differing in ploidy level.
Leopold’s research has taken him well beyond Colgate University’s campus. The study site for his thesis is Nelson Swamp in Nelson, N.Y., a mixed conifer wetland where all three dryopteris species coexist. But the lab’s broader work has brought him further afield: to the Great Dismal Swamp in Virginia, and, very memorably, to Alabama, where the team surveyed endangered ferns from jet skis.
“Тhey are on overhanging rocks, because they have to live in these dark, damp environments. So we’d kind of jet ski up, and then take a sample or do a count, make sure the population’s doing okay,” Leopold recounted.
Back in more familiar terrain, Leopold logged roughly 90 hours of fieldwork over the summer of 2025, clamping a LiCor 6400 — a specialized gas exchange machine — onto fern fronds to measure photosynthetic rate, respiration and stomatal conductance. In the lab, he prepared samples for stable isotope analysis and examined stomata under a 40x light microscope, using their size to check which ploidy level he was looking at.
“You just put the machine in place, it spits out the numbers for you, put that on a computer, then you can graph it and do whatever analysis you need,” Leopold said. “There are few things more peaceful than being out in the middle of the forest on a nice day in the summer, just surrounded by all these plants. You set up the machine, you let it work, and you kind of just walk around.”
Leopold first joined the Watkins Lab in the summer after his first year, when a relationship built through office hours led to an invitation to do summer research. He has been there ever since, recruiting more students to join the lab and mentoring younger researchers in field methods and microscopy.
The work, he said, is always more urgent than it might appear to outsiders.
“I think polyploidy is really interesting, and especially pertinent when you think about climate change,” Leopold said. “There is a wealth of literature claiming that polyploidy is advantageous when it comes to stress tolerance. As the world gets warmer, polyploids could have an advantage over diploids.”
This possibility — that the extra chromosomes carried by dryopteris xbootii might make it better equipped to survive a rapidly warming world — is only part of what makes the research feel timely. Ferns already dominate much of the forest understory and play a significant role in controlling seed germination and forest regeneration. Understanding which species will thrive, and why, matters, Leopold believes. He also just wants people to simply look more closely.
“Ferns are underrated, because at first they all look the same,” he said. “And then you walk up and take a closer look — some of them are more frilly, some of them are more cut. It’s like, whoa. These are cool.”
He hopes to submit his thesis work for publication, along with a separate manuscript he co-led with another Colgate student. After graduation, he plans to pursue clinical research at a hospital, leaving botany behind, at least professionally. But Leopold will take his appreciation for ferns with him far into the future, even when that means stopping every ten seconds on the trail to take a closer look.
