For all anyone knows, the scrappy plants with the thimble-size white flowers have been sprouting from rocky Pennsylvania cliffs for ages. Yet no one noticed them until a few years ago, when a Bucknell University botanist and colleagues were rappelling down a 350-foot cliff face in Shikellamy State Park.

The identity of the rare species, Heuchera alba, was determined in 21st-century fashion, after the group posted a photo on Twitter.

Then came another surprise: On a return trip, the scientists noticed an unusual bee hovering over its petals. Upon consulting insect experts, they learned it was an alumroot cellophane bee, so named because it wraps its underground nests in plasticky film that resembles cellophane. No one had reported seeing it in the state for more than a century.

That’s more or less where things stood until this year, when Anais Barnes showed up.

A recent transfer from Community College of Philadelphia, she had earned a full scholarship to finish her undergraduate studies at Bucknell’s leafy campus in rural Lewisburg, Pa., and was eager for a hands-on project after months of remote learning during the COVID-19 pandemic. An adviser steered her to Chris Martine, the botanist who had found the first few populations of the rare plant. And by the start of June, she and another undergraduate, Maddie Wickers of Phoenix, were on the road.

Find me more plants and bees, Martine told them. And find them they did, sometimes driving 200 miles in a day to scope out potential spots along the Susquehanna River valley. The two young women were so successful — collecting specimens of the plant at 20 locations and the bee at six — that they will present their findings this month at a national botany conference.

They also are performing genetic analysis of the samples. But the initial phase of the project involved the same low-tech tools that naturalists have used for centuries, such as wooden plant presses with stout canvas straps. Plus some skillful maneuvering to trap the flying insects.

“We’re handy with a net,” said Barnes, 22, who will be a senior this fall.

Both she and Wickers, 20, a rising junior, are biology majors, yet neither knew much about plants until starting work in Martine’s lab a few months ago. But in a way, Barnes could relate to the idea of a plant thriving in an unexpected environment. She grew up in Frankford, graduating from Franklin Towne Charter School, and now is at a private university where the annual tuition and room and board exceed $74,000.

“It’s definitely a different world,” she said.

#BlackBotanistsWeek

She is among just 4% of students on campus who are Black, yet she feels welcome, especially in the botany lab. Along with Martine, her co-adviser on the plant-bee project is Tanisha Williams, a postdoctoral fellow who in 2020 founded Black Botanists Week, an online campaign to highlight the work of Black researchers who specialize in plants.

As in most sciences, people of color are underrepresented in the field of botany, but Williams thinks they are more numerous than many realize. Before launching the online campaign, she had never met a Black botanist. But 11 others quickly responded to her first tweet. And by the end, the top 50 users of the #BlackBotanistsWeek hashtag had interacted with 223,000 people, she and colleagues reported in the journal Taxon.

“We’re out there,” Williams said. The second annual Black Botanists Week is scheduled for July 26 to 31.

Martine, the professor, is all about promoting the value of hidden gems. In addition to amplifying the accomplishments of his lab members, he is a booster for botany as a whole — contending that it is something of an underdog within the broader field of biology.

A decade ago, lamenting that most nature videos seemed focused on animals, he launched his own YouTube series, Plants Are Cool, Too!, cosponsored by the Botanical Society of America.

All about the stamen

That’s how the mystery of the rare Heuchera plant — pronounced HEW-ker-uh — came to light. Martine was interviewing other scientists from the Pennsylvania Natural Heritage Program, a group that documents the status of flora and fauna for conservation purposes. They were collecting a different plant that day in 2017, dangling from ropes on the riverside cliff.

Along the way, Martine snapped a photo of what he thought was Heuchera americana, a fairly common plant, and posted it on Twitter. Nope, replied biologist Ryan Folk, then at the Florida Museum of Natural History. Instead, he said, it looked like Heuchera alba, a globally imperiled species then known to exist only in scattered populations in Virginia and West Virginia.

To the untrained eye, the difference is subtle. In the more common species, the plant’s stamen — the slender filament that produces pollen — protrudes by 1 or 2 centimeters from the flower. In the rare version, the stamen is tucked inside.

Once Martine knew what to look for, he went back to Bucknell’s historic plant collections, maintained in climate-controlled, floor-to-ceiling cabinets in the university’s Manning Herbarium. He found four Heuchera specimens, labeled either as americana or pubescens, another common variety. Both are cousins of a common garden plant called coral bells.

But again, it was a case of mistaken identity. Upon close inspection, he saw that all four actually were H. alba, the rare version he had just stumbled across on the cliff.

And there was another clue. The label on one of the misidentified specimens said it had been found at a place called Gundy’s Farm, in 1905.

“I thought, ‘Where have I heard that before?’” he said. “Then I remembered I had this old photo in my desk.”

The photo, which someone had left behind when Martine came to Bucknell in 2012, was labeled with the same name, Gundy’s Farm. It depicted a team of early 20th-century naturalists — the men in suits, the women in bonnets and dresses — beneath a cliff that Martine recognized was near campus.

He and colleagues soon went back. The farm above the cliff is long gone, carved up for development, but sure enough, the researchers found samples of H. alba. They scouted a few more sites with similar rocky cliff faces, and found the plant there, too, as well as the unusual cellophane bee that pollinates it. But Martine wanted more.

Enter the undergraduates

In June, Martine gave Barnes and Wickers two dozen possible locations, all along sunny cliffsides with slightly acidic rock that the plant seemed to prefer. They found it at 20 sites, suggesting that the plant is less rare than anyone realized — though in many spots it is being crowded out by invasive species such as Japanese honeysuckle. The students placed one plant from each site in a wooden press, taking it back to the lab to be dried in an oven, and they also snipped samples of leaves for later genetic analysis. They trapped bees with a net, then knocked them out with alcohol and placed them in vials.

The pair, who were accompanied by Martine and Williams on some trips, were quick to appreciate the importance of their long, hot hours scrambling on rocks. Scientists can’t tell which species are disappearing, and how to maintain them, if they don’t know what’s there to begin with.

“Preserving biodiversity is really the key,” Barnes said.

Yet when the two women told friends and family how they were spending the summer, there were some puzzled reactions. As Barnes explained the follow-up lab work, however, they found it more relatable.

“When I got to the DNA part, they got interested,” she said.

Barnes’ friends know she wants to be a forensic scientist after graduating, and DNA analysis would be one of the tools of her trade, she said, speaking in the lab after a recent specimen-collecting trip.

Overhearing from across the room, Martine was quick to make a forensics-related plug for botany.

“There was a great CSI episode one time where they pulled plant material out of somebody’s throat,” he called out.

The two women present their findings at the Botany 2021 conference on July 19. Like so many other events during the pandemic, it will be virtual.

They are a bit nervous to be appearing on the schedule alongside researchers with Ph.D. degrees.

“It’s a little daunting, only being an undergraduate,” said Wickers, who is thinking of a career in environmental law.

Martine, having seen the pair at work this summer, is confident they will hold their own. Though neither has plans to follow his career path of botany, he feels they have a good grounding in the scientific method: skilled at asking questions, challenging assumptions, and confronting whatever puzzles may come their way.

“The lesson here,” he said, “is that there’s still a lot of stuff out there to be discovered.”

Whether it’s plants, bees, or the talents of future young scientists that he will send out on the road, plant presses and insect nets in hand.