Mounted on acid-free paper, and filed away in the climate-controlled storage area of the University Herbarium, are plants dating back to the 1820s and ’30s.
And while staff members are busy imaging roughly 20,000 key specimens at high resolution — just a fraction of those held at the Herbarium — the actual specimens, mounted on paper for ease of handling, will for the foreseeable future continue to be essential for research. “You can’t extract DNA from an image,” says Tony Reznicek, assistant director, curator and research scientist at the Herbarium.
Ranked as the third-largest university herbarium in North America, behind Harvard University and the University of California-Berkeley, the U-M Herbarium holds about 1.7 million specimens. They mostly are mounted on 11-by-16-inch sheets of paper collected in folders color coded to denote four world regions. Among the Herbarium’s holdings are 96,000 algae specimens, 280,000 fungi and 57,000 lichens, besides the more typical land plants.
On each sheet containing a mounted specimen is a label, typically in the lower right corner, denoting the geographic location of the plant (now typically with GPS coordinates), a description of its surroundings when collected, who collected it and when.
The collection is housed in the former M-Stores warehouse just southeast of State Street and I-94. Offices adjoin the collections area, known in the herbarium profession as “the range.” The range is dominated by neat rows of dark green and tan metal cabinets, each holding 2,000-2,500 specimens.
Paul Berry, professor of ecology and evolutionary biology, and curator and director of the Herbarium, says the range is kept at 37 percent humidity and 68 degrees because these conditions are optimum for heading off the reproduction of insects, which are a major threat to the collection.
There are about 600 registered herbaria in the United States, and about 4,000 worldwide. Not all are associated with universities, Berry says, and some are connected to botanical gardens or national museums such as the Smithsonian Institution in Washington, D.C. Herbarium collections are maintained by botanists and plant collectors who have searched worldwide to document the diversity and distribution of plants. The study of herbarium specimens forms the foundation of our understanding of plant relationships, geographic distributions, economic usefulness and even their molecular makeup.
Typically, researchers may study herbarium specimens to perform measurements, dissections or DNA testing, as well as to map the occurrence of species at various scales.
The Mellon Foundation is currently funding a project at the Herbarium to digitize 20,000 specimens of critical importance to researchers worldwide. This digitized collection is available online through the U-M Digital Library and the Global Plant Initiatives websites.
“We are trying to make our collections more accessible to the public using virtual tools, and there are moves on the horizon to expand digitization efforts here and at other institutions nationwide,” Berry says. “We will soon launch a website on Michigan Plants, which represents an update from the previously published three-volume ‘Michigan Flora’ by Emeritus Professor Ed Voss.”
Technological advancement has had a powerful impact on our use of collections. “We are increasingly able to obtain molecular results from herbarium specimens, potentially of now rare or even extinct species, and more of the specimens are being imaged or databased and shared with users via the Internet,” Berry says.
DNA typically is extracted from specimens 20 years old or younger, but it also can be removed from 100-year-old specimens, Reznicek and Berry say.
Staff working at the Herbarium include four faculty level curators — three are shared with the Department of Ecology and Evolutionary Biology — three collection managers who oversee the care of collections and loans to other institutions, a plant mounter, a half-time research scientist, and several emeritus professors and a specialist working on the digital database.
Part-time students and postdoctoral fellows who work on projects with a curator also are employed at the Herbarium. “Curators do research on different groups of plants or areas of the world, and the rest of the staff support those activities and the active use of the Herbarium for researchers worldwide,” Berry says.
“Ultimately we strive to contribute knowledge and expertise about plants and fungi at both local and global levels, as well as helping to understand and document the growing loss of biodiversity worldwide.”
Jane Sullivan, graduate student coordinator in the Department of Ecology and Evolutionary Biology, on working at her alma mater:“I always thought it would be a great place to work, and for me it’s turned out to be the case.”
Artist Wangechi Mutu’s lecture “My Dirty Little Heaven,” 5-6:30 p.m. Nov. 18 in the Michigan Theater.