In 1874, professor David Starr Jordan published a small feature in The American Naturalist documenting all of the plant life found on Penikese, a tiny outcrop that is part of the Elizabeth Islands. Mr. Jordan, who would go on to be the founding president of Stanford University, was working at Louis Agassiz’s Anderson School of Natural History on Penikese, a pioneering but short-lived field station that directly inspired the Marine Biological Laboratory in Woods Hole and other prominent research institutions.

One hundred and fifty years later, botanical surveys are regularly still taking place on Penikese, making its flora some of the most richly documented along the east coast. The Penikese School, a nature-based educational nonprofit on the island, plans to celebrate the anniversary of the surveys and highlight the island’s longstanding scientific pedigree with events in the new year.

“I think it’s remarkable that this tiny island, the awkward cousin of the Elizabeth Islands, has this deep history of scientific data gathering,” said Kimberly Ulmer, the executive director of the Penikese School.

Penikese is a 75-acre, claw-shaped island in Buzzards Bay, just north of Cuttyhunk. It has led a varied life over the years, though science was at its core since Mr. Agassiz, in the waning years of his life, founded the Anderson School in 1873. A renowned Harvard College scientist whose work was later blemished by some of his racist beliefs, Mr. Agassiz focused on outdoor learning, eschewing textbooks in favor of the natural world. While that may seem obvious now, in the 1800s the idea was revolutionary in academia, Ms. Ulmer said.

Mr. Agassiz died in 1873, and his son was able to keep the school running for another year, before it dissolved.

Penikese was once home to a leper colony. — Ray Ewing

Despite existing for only two years, its influence stirred alumni to found the Marine Biological Laboratory, the Cold Spring Harbor Laboratory in New York and Stanford’s Hopkins Marine Station.

“Those two summers really laid the groundwork for observation science,” said Ms. Ulmer. “I can’t really believe all of them got their inspiration from a summer on little old Penikese.”

In that first survey, Mr. Jordan found 114 different species on Penikese and Gull Island, a neighboring sandbar that is now a spot favored by seals at low tide. The forest that had once been said to have thrived on Penikese was long gone.

“The island as it now appears is absolutely treeless and nearly shrubless, and it is scantily covered with pasture grasses which furnish subsistence to flocks of sheep,” Mr. Jordan wrote. “Altogether it is about as barren looking a pile of rock and stone as one could imagine.”

But Mr. Jordan saw the potential in rounding up what species he could find.

“This list may have a special interest to future students at Penikese and also a general interest to botanists, as showing which plants survive a prolonged struggle for existence against grass and sheep,” he wrote.

After the school’s demise, Penikese famously became a leper colony, and, later on, a school for delinquent boys. The state purchased the island in 1904, and a couple ran the leper hospital there for 16 years, putting a halt to the botanical observations.

In 1923, two years after the hospital was closed and the buildings burned down, workers from the U.S. Bureau of Fisheries and the Marine Biological Laboratory took up the botanical mantle, and published their findings the next year.

After 50 years, the scientists found that up to 44 species listed in the original survey had disappeared from Penikese, which had been eyed to become a bird sanctuary. But they also found 94 new species, bringing the list up to 166 different plants.

The school will host a series of events in the coming year, celebrating the island's scientific heritage. — Ray Ewing

“The presence of such a large number and proportion of invaders indicates that ecologically the island is progressing rapidly, since it has not been free of sheep for more than a dozen years,” the scientists wrote. “The record of its further changes should be followed carefully by the botanists of this region as giving a clear picture, very definitely outlines, of vegetational succession in a circumscribed area.”

Surveys progressed about once every 25 years, with papers published in 1948, 1976 and then in 1999. By 1999, woody vines and shrubs had taken over Penikese after farming ceased on the island.

“In the absence of further disturbance, it is possible that Penikese will again become forested with red cedar,” scientists found.

Disturbance did come, however, to Penikese. The state, which still owns the island and runs a bird sanctuary there, has been holding regular controlled burns on the island, making it more habitable for terns and other birds

“I think in general, there’s fewer woody species on the island than back then,” said Robert Wernerehl, a botanist with the state’s Natural Heritage and Endangered Species Program. “The coverage of shrubs is much less.”

Mr. Wernerehl led a survey of the island earlier this year, and botanists are working to analyze their findings.

While past surveys would take specimens and measure them up against other dry and mounted plants in herbarium sheets, the state has taken a more modern approach. Specimens are being posted on the iNaturalist app, where botanists from across the globe can offer identifications. With so much of the flora being non-native, this can help state scientists, said Mr. Wernerehl.

In general, the state is seeing more grassy coverage on Penikese, which is favorable for the nesting birds.

Geese have also flocked to the island, and their fondness for defecating in the island’s ponds has devastated the marine plant species that had been documented in the past.

“The pond flora is probably more depauperate than in the past,” Mr. Wernerehl said.

The state does believe though that the island is host to a species of switchgrass that may only found on the Elizabeth Islands, as well as an endemic sprangletop. Samples have been sent off to experts to see if they are truly their own subspecies of plant.

Ms. Ulmer, who has several talks on Penikese history planned for the Vineyard in 2025, will also hold a celebration of the scientific work on Penikese in July. She and Mr. Wernerehl wanted people to know about the long history of research on Penikese.

“I think that’s a little bit special and unique,” Mr. Wernerehl said of the longstanding botanical surveys. “The Elizabeth Islands chain and Dukes County have a special place for research.”