Brown herbarium documents what grows in Rhode Island

            The herbarium at Brown University has been a repository of plant specimens from throughout southern New England and around the world since it was established 150 years ago.  It maintains what herbarium director Rebecca Kartzinel calls “the physical record of a species in a particular place” – pressed leaves, flowers, stems and sometimes roots with detailed notes about where and when it was collected.

            Among the 100,000 specimens stored in folders in climate-controlled and insect-proof cabinets are samples from the early explorations of the American West, as well as from Cuba, New Zealand, New Guinea and elsewhere.

But the overwhelming majority of the 14,000 plant specimens from Rhode Island were

Herbarium Director Rebecca Kartzinel (Todd McLeish)

collected more than 100 years ago. And a great deal of the Rhode Island landscape has changed since then, due largely to the climate crisis, invasive species and habitat destruction. So Kartzinel is leading an effort to collect specimens of every plant now found in Rhode Island.

“We have a good representation of plants from 1870s Rhode Island, and we want to have a good representation of Rhode Island’s flora now,” said Kartzinel, a research professor in the Brown Department of Ecology and Evolutionary Biology, who took over the directorship of the herbarium last May. “That means we have to collect everything that grows in Rhode Island.

“Knowing what’s here now is important because things are rapidly changing,” she added. “The data could be used to compare with historic records or for producing more accurate range maps or for analyzing what factors are impacting the changes, and much more.”

The project was launched four years ago by the previous herbarium director, Tim Whitfield, who focused his own specimen collecting efforts in the Cumberland area. Botanist Beth Dickson, who worked in Alberta, Canada, for 24 years before retiring to Rhode Island, is spending much of her free time collecting specimens in South Kingstown and Charlestown.

“To actually collect every species, if it’s even possible, will probably take many years, since many plants are best found only in certain seasons and specific habitats,” said Dickson, who uses Google Earth imagery to identify various habitats to visit. “Having a good specimen gives adequate material to do comparison studies of anatomy, morphology and biochemistry that may be useful in the future.”

When in the field, Dickson carries a trowel, clippers, notebook and a field press and makes note of the habitat and the other species growing near the collected specimen. Once she returns home, she uses a dissecting microscope to identify each specimen before pressing it and letting it dry for a week or more.

While Dickson is focused on collecting the area’s most common plants, amateur botanist Doug McGrady searches statewide for rare plants to contribute to the herbarium collection. And Kartzinel is taking a systematic approach to overseeing the project by seeking out habitats and species that are underrepresented in the collection, and by identifying species from the historic records that haven’t been found recently and trying to track them down on the landscape.

Historically, herbarium specimens were mostly used in the describing and naming of species. Scientists seeking to determine whether a new species had been discovered would use herbarium specimens for comparison purposes.

While specimens are still studied in this way, most recent uses of the collection have involved DNA studies.

“That means our collecting must be done with DNA sequencing in mind,” said Kartzinel. “We often collect additional material so we don’t destroy the specimen. And we dry them with minimal heat so we don’t destroy the DNA.”

In addition, the entire collection is in the process of being digitized so scientists can conduct their studies without needing the actual specimen in hand. Anyone can view the digitized collection online. Tours of the herbarium for garden clubs and other interested groups are also offered by appointment.

Some samples are even loaned for use in exhibits. The Providence Athenaeum has included several specimens from the Brown herbarium in its Walt Whitman exhibit, which runs until January 5.

“These specimens aren’t just useful within the scientific community,” Kartzinel said. “From a museum perspective, it’s important to recognize that you never know what is going to be useful in the future. So it’s our job to keep that documentation. If we stop collecting, then that’s the end of our record. It’s the continual temporal record that’s important.”

This article first appeared on EcoRI.org on November 30, 2019.