The world’s largest and most diverse systematic collection of seeds of flowering and coniferous plants is now part of the National Arboretum.
The collection contains approximately 125,000 dried seed and fruit samples from plants throughout the world. Over 27,000 different species of
plants representing 397 families and 13,000 genera of plants are represented in this valuable collection. The samples are stored in either glass
vials or plastic bags. The entire collection is kept in a secure, moveable compact storage facility.
The National Seed Herbarium serves several important roles, including helping to document biodiversity and seed types of species, varieties,
and cultivars, some of which may be extinct. It is an important tool for identifying unknown seeds, and it supports research programs relating
to seeds. The collection also serves as the primary source of information for the most important references for seed identification of noxious weeds,
legumes, and families of seed plants published by the USDA. [Images above were taken by APHIS technician Robert Gibbons].
The seed collection was transferred to the Arboretum in late 2007 from the Plant Sciences Institute of the Beltsville Agricultural
Research Center in Beltsville, Maryland, where it resided for many years.
The Seed Herbarium is a companion to and complements the arboretum herbarium,
which contains over 600,000 dried specimens of twigs, branches, flowers, and fruits of the world’s flora. If there’s a perfect entity in nature, it would have to be seeds. These compact packages—in an astounding array of sizes, shapes, colors, and textures—contain all the reproductive material a plant needs for making hundreds, if not thousands, more of itself. With their streamlined anatomy and assortment of hooks, spurs, burs, and barbs that even the most inventive engineers couldn’t have dreamed up, seeds are capable of journeying hundreds and even thousands of miles. Think of cockleburs that latch onto a rabbit’s fur or a hiker’s socks. Or maple tree “flippers” parachuting down through the treetops. Or dandelion fluff blowing in the wind. But not everyone’s applauding these efficient voyagers. That’s because some plant species—which are typically well behaved in their home territories—can trigger ecological chaos in other environments. For instance, spotted knapweed, leafy spurge, and garlic mustard, to name a few, have all invaded U.S. lands, displacing thousands of acres of native vegetation that people, livestock, and wildlife depend on. Federal inspectors are at the front lines of the battle against these invasives. Stationed at ports around the country, they stand ready to screen incoming plant materials for possible unwanted stowaways. But trying to identify hundreds of unusual seeds and fruits—from as far away as Asia, Australia, or Central and South America—is a daunting task. That’s why seed experts—systematists with the Agricultural Research Service (ARS) in Beltsville, Maryland—play such an important support role in helping to prevent entry of damaging weeds into the country. These researchers may be called on by other agencies, such as the USDA’s Animal and Plant Health Inspection Service, to help identify strange and suspicious seeds. Trying to identify the world’s numerous seeds isn’t like strolling through the garden to note the names of its flowers. To do it right, and as swiftly as possible, ARS systematists, including botanist Joseph Kirkbride (FNPRU), tackle their mystery subjects armed with microscopes, identification guides and booklets, and a collection of thousands of seed and fruit samples for reference. For example, consider legumes—the family that gives us peas, peanuts, soybeans, and lentils. Right now, taxonomists organize this group’s widely varying and numerous members into 650 genera, or groups of related species. Sometimes, though, one or two subtle features may be all there is to help distinguish between two legume species. When researchers analyze a legume seed under a microscope, they usually study the embryo inside. “If we happen to see microscopic hairs growing on this tiny embryo,” says Kirkbride, “we’re likely to get pretty excited. That’s because, by finding those little hairs, we know we can rule out over 16,000 legume species. Only five legumes are known to have them.” To help make identification go as smoothly as possible, ARS’s Kirkbride and colleagues have developed an online database for helping port inspectors, researchers, and others identify seeds and fruits that stump them. “This new database should at least shrink the universe a little, in terms of the countless seeds and fruits out there,” says Kirkbride. “Most seeds look pretty uniform to people, so we hope our tool can ease some of the difficulty that comes with tedious identification.” Name That Seed! When it comes to seeds, you can’t say, “seen one, seen ‘em all.” In fact, as Joseph Kirkbride, an ARS botanist in Beltsville, Maryland, knows, there’s incredible diversity among them. For instance, the world’s smallest seeds, produced by orchids, can’t be seen with the naked eye. “The heftiest come from rainforest-dwelling legumes and can weigh close to 2 pounds,” he adds. An expert on seeds and fruits, Kirkbride works at the U.S. National Arboretum's Floral & Nursery Plants Research Unit in Washington, DC. He’s also director of the U.S. National Seed Herbarium, which is now housed there. Finding a seed in the seed herbarium is like hunting down a book in a library: They’re organized alphabetically according to the family or genus they belong to. But the collection is more than just an archive or museum. “We’re always using the collection for research purposes and for help in identifying unusual seeds,” says Kirkbride. Recently, many of the herbarium’s thousands of seeds and fruits were taken out of their drawers. One by one, each was carefully scrutinized, sketched, and photographed. Why? Kirkbride and colleagues have spent the last 6 years compiling an online database that will help inspectors identify seeds and fruits that have hitched rides into the country—in shipments of grain, horticultural plants, and other plant cargo. It will also serve as a tool for researchers studying ecology and biology. This first-of-its-kind online resource is called “The Family Guide for Fruits and Seeds.” It will soon be online here at the US National Arboretum website. But for now, you can still access it here. The database includes all 418 plant families that produce either fruits or seeds. While many fruits just so happen to be deliciously edible, those beauties are really just a fleshy carapace for housing plant seeds. Along with unwanted seeds, our most important foods—rice, wheat, and corn—are also represented in the database, since these vital plants all sprout from some sort of seed. More than 3,000 photos, taken by APHIS technician Robert Gibbons, illustrate the great diversity of seeds. Many had to be magnified more than 100 times for their delicate features to come into focus. ...Portions of this page are edited and abstracted from an article reported by
Erin K. Peabody, Agricultural Research Service Information Staff and published in the
March 2007 issue of Agricultural Research magazine.
U. S. National Seed Herbarium Moves to the Arboretum
Davidsonia-plum family; Davidsonia pruriens fruit (Image by Robert Gibbons).
Seeds of Knowledge
Aster family; Calendula officinalis seed (Image by Robert Gibbons).
Tedious and Painstaking Work
Some of the more than 3,000 photos in the U.S. National Seed Herbarium. [The images presented here were taken by APHIS technician Robert Gibbons].
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Last Updated May 6, 2008 12:42 PM
URL = http://www.usna.usda.gov/Research/NatioanlSeedHerbarium.html