Perfectly preserved: The MMA’s dried plant collection

By Lucy Apthorp Leske

(Nov. 23, 2022) On a visit to the Maria Mitchell Association research center this past weekend, I ran into ornithologist, natural historian and fellow Inquirer and Mirror columnist Ginger Andrews.

She and the MMA team had pulled out some lovely and long dead loons for inspection along one side of the center table. On the other lay pages of perfectly preserved, pressed and dried members of the legume plant family from the MMA collection.

As we were standing there reflecting on everything from species diversity to habitat loss to the origin of the North American wild turkey, Ginger relayed an observation from a fellow birder. To paraphrase, there would be no birds on this planet without the generosity of grasses. I thought about that for a minute and extrapolated that there would be no animals at all without the generosity of plants. For that, I am thankful this Thanksgiving.

I am also thankful for the collection of preserved native and introduced plants housed at the Maria Mitchell Association. Technically, a collection of dried and preserved plants is called an herbarium. Originally referred to as a “dry garden” or hortus siccus, herbaria were conceived in the 16th century by Luca Ghini, professor of medicine and botany at the University of Pisa, who first developed the method of drying and preserving plants, attaching them to paper and fixing them as leaves in a book.

Later, plant taxonomist Carl Linnaeus picked up the practice but eschewed the book format, instead storing sheets or “vouchers” loosely in cabinets so they could be individually removed for study. Herbaria became very important tools for classifying and cataloging plants around the world, documenting new discoveries and comparing species from different geographic locations. As centuries wore on, amateur collectors joined the fray and often set about building personal herbaria as a hobby.

Today, the world benefits from the work of all the collectors who picked and preserved plants. A couple of centuries ago, no one could predict that preserving plants would transform from an academic taxonomic exercise to a crucial means for understanding species diversity and extinction.

I was fortunate to speak last week with several paleobotanists who study million-year-old plant fossils to understand what causes extinction and how plants and ecosystems evolve.

Not only is it helpful for them to compare and contrast extinct plants with collections like the one at the Maria Mitchell Association, it is also crucial to document and catalog plant species that may not be around much longer. Thank goodness for all of the plant collectors who came before us and preserved a part of our ecological and botanical heritage.

According to the Brown University herbarium website, there are several thousand herbaria around the world ranging from small collections like the Maria Mitchell Association’s, with about 6,000 vascular plant specimens to the Muséum National d’Histoire Naturelle in Paris with around 9.5 million specimens.

Here in the United States, the William & Lynda Steere Herbarium at the New York Botanical Garden in the Bronx is the largest with over 7.2 million specimens.

It accumulated this vast number from around the world through the activities of its own scientists and staff over many years of field research and collecting, as well as through the donation or acquisition of individual herbaria like the collection of Frank MacKeever, botanist, columnist, prolific collector of Nantucket flora and author of the book “Native and Naturalized Plants of Nantucket” (University of Massachusetts Press, 1968).

Chief custodian of the New York Botanical Garden herbarium for 18 years, he traveled all over New England, Cape Cod and the islands and collected thousands of plants, preserving and depositing the results in his personal herbarium.

Many of the MMA’s specimens were contributed by MacKeever. What is most unusual is that Nantucket has an herbarium at all. Most are associated with universities or botanical gardens. That we have one here is quite rare.

Once upon a time, the only way to view the MMA, MacKeever’s or anyone else’s herbarium was to travel to the herbarium itself, gain access to the temperature and humidity-controlled cabinets, and view individual vouchers just like I was doing last weekend at the MMA .






Like all dried plants, most are quite fragile. After pressing and drying the original collected plant, the stems are attached to oil- and acid-free paper with glue or cloth tape.

Although the drying process saps moisture and bright color from the tissue, enough of the seeds, flower petals, twigs, leaves and plant structure remain to provide important clues for scientists who seek to understand the diversity of our plant world.

During my MMA visit, Andrews pointed out on one sheet the telltale signs of leaf miner in the leaves of one specimen, an interesting fact that might be of interest to people studying our ecosystem.

Some of the MMA plants are quite old and reveal intriguing stories. Julia Blyth, the MMA collections manager, tells me the oldest is a specimen of broom crowberry ( Corema conradii), collected by Mrs. Nathaniel (Katherine) Starbuck on May 6, 1878.

The sheet of Amelanchier nantucketensis collected by Eugene Bicknell near the border of Trot’s Swamp on June 10, 1908 contains the description, “Type for young fruit and leaves of young branch.” Multiple labels and notes are attached to the sheet, illustrating the efforts of other botanists and herbaria to verify this as a distinct species specific to Nantucket.

Another sheet of Bartonia virginica (common name screw stem), collected by MacKeever on Aug. 16, 1959 near Miacomet Road notes, “An unexpected colony about 100 feet from the famous Nantucket heather, Calluna vulgaris.” Today, the area is riddled with development. Are the plants still there?

I asked Kelly Omand, plant research ecologist and botanist at the Nantucket Conservation Foundation, if she finds herbaria relevant today, given the advances in technology like the iNaturalist app in scanning and cataloging plant species. She insists that physical vouchers are still essential for research, botanical history and genetic testing.

Thanks to the wonders of technology, herbaria like the MMA and New York Botanical Garden are methodically photographing and digitizing their collections, enabling people around the world to visually access these astonishing collections for close inspection and comparison.

Blyth explained that the MMA is now a member of the Consortium of Northeast Herbaria which unites 46 herbaria from Pennsylvania to Canada to “. . . provide online access to sample data housed in members institutions, with particular emphasis on collections from the region.” Free access to the digitized collections can be had through its website https://portal.neherbaria.org/.

Thousands of specimens can be seen there in startling detail, including many from Nantucket like a Lilium philadelphicum (wood lily) collected from a “field near Polpis”” on July 22, 1892, or an Aster concolor (now reclassified Symphyotrichum concolor) collected “on the moors” in 1903 by Emile F. Williams.

Blyth says that nearly three-quarters of the MMA collection has been digitized, with more to come. Over the years amateur botanists, students and researchers like the late Wes Tiffney, former director of the University of Massachusetts Nantucket Field Station, have contributed to the collection. Oman has added over 300 specimens in recent years and, with Sarah Bois, Ph.D., of the Linda Loring Foundation and other collaborators, is in the process of conducting a county-wide update of both indigenous and introduced naturalized plant species.

The MMA welcomes new specimens, especially of plants it doesn’t have yet. The fact is that herbaria, once considered dead ends for arcane research, are important resources for our planet as we face species decline, climate change and diminishing biodiversity.

Herbaria contain clues for scientists on how plants adapt or respond to different environmental conditions around the world. I am grateful that Nantucket’s wonderful herbarium and plant collectors are part of the larger global effort to collect and understand our diverse plant community.

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