September 2018: Seeds

 

 

Platanus occidentalis (sycamore), three yellow ball-like seed heads and detail of seeds

Seeds can be defined as: “fertilized, mature ovules that are the result of sexual reproduction in plants”. Not every plant produces seeds, but those that do rely on them to replicate themselves for years and seasons to come.

 

Seeds have immense biological, social, and economical importance. According to Carolyn Fry, author of the book, “Seeds: a natural history," Western civilization may have never arisen without seeds. Although there are other crops, like potatoes, and plants that developing human societies have relied on, it is argued that Earth would not have been able to sustain such a large human population without seeds.

 

Today, the three most important crops in the world are: maize, wheat, and rice. These three annuals from the grass family provide approximately 60% of the world’s food intake. What makes them so appealing for large-scale human consumption is that their seeds are rich in essential carbohydrates, protein, vitamins and minerals. Additionally, they have fast life cycles, making them easy to cultivate in large numbers. (Fry, 2016)

 

Even before humans began to farm, seeds played an essential role in the diets of hunter-gatherers. “Australian aborigines in some locales are known to have relied on seeds of native millet or wild fruit and other seed species.” (Milton, 2000) As far back as 21,000 years ago, acorns were consumed by hunter-gatherer populations. (Fry, 2016) The image below depicts acorns from the Quercus alba (white oak) and the quercus macrocarpa (bur oak).

Quercus alba (white oak) and Quercus macrocarpa (bur oak), detail of two acorns side by side with nuts facing up, showing dark brown nut and shallow cup of white oak on left and deep, shaggy-fringed cup of bur oak on right

 

According to the Botanic Gardens Conservation International, as of April 4, 2017 there are 60,065 species of tree world wide! Here at The Morton Arboretum, we have approximately 1470 different tree species. With that being said, it could be expected that different trees would have their seeds “packaged” in different ways. The eight primary types of tree seed type are: winged, freshy fruit, nut, nutlet, drupe, follicle, pods, and capsule.

The images and descriptions below are the different types you can most commonly find here at the Arboretum! Click on the image to be linked to a detailed record of the photograph and have the chance to view additional photos!

 

Winged seeds are most commonly seen in maples, sycamores, birches, alder, and conifers. In the photograph below is an image of an Acer campestre (hedge maple) fruit. The image depicts the detail of the hanging fruit with paired seeds and wings at 180 degree angle. According to BRAHMS online, you can find various hedge maples at The Arboretum here.

Acer campestre (hedge maple), detail of hanging fruit with paired seeds and wings at 180 degree angle


Fleshy fruit seeds are typically seen in berries, arils, and other fruit producing trees (apples, pears, etc). Below is a photograph of the seeds and cones of a Juniperus virginiana var. crebra (eastern red-cedar). Red cedars and other junipers are important to many types of wildlife. Their twigs and foliage are often eaten by hoofed browsers, and their berries are eaten by both mammals and birds. You can find them at the Arboretum at these locations!

Juniperus virginiana var. crebra (eastern red-cedar), detail of seeds and berry-like cones on ground

 

Nuts are defined as a “single-seeded fruit inside a woody seed coat”. Common nuts are acorns, chestnuts, beechnuts, hazelnuts, mockernut and hickory. The photograph below depicts a Quercus (oak), seedling. In the image, you can see the seeding bursting from the acorn. If you are interested in seeing the various oak species here at the Arboretum, check out these locations!

Quercus (oak), seedling detail


Nutlets are a small nut. Below is a photograph of an Ostrya virginiana (ironwood), fruit detail and tree. The inset photograph depicts the fruit with its seeds exposed. To check out the ironwood on Arboretum grounds, see these locations.

Ostrya virginiana (ironwood), fruit detail and tree

 

“Drupe are a fleshy fruit with one or more seeds, each being enclosed in a stony casing.”  Common examples of drupes are peaches and plums. Despite their name, walnuts are actually a member of the drupe family. Below is a photograph of a Juglans nigra (black walnut) nut. The black walnut can be found at these locations around the Arboretum.

Juglans nigra (black walnut), fallen dark brown rounded nuts , one with irregular deep groves and jagged broken ridges, one cut open down center, one with smooth surface

 

Follicle are a dry fruit containing more than one seed, that split open along a seam. An example of a tree with follicle seeds are magnolias. Magnolias can be found around the Arboretum in these locations. Below is an image of a Magnolia virginiana (Sweetbay Magnolia, seed.

Magnolia virginiana (Sweetbay Magnolia), seed

 

Pods are considered to be a dry many seeded fruit that open naturally. A tree known to have flat, thin pods is the American Elm. You can find them at the Arboretum here! Below is an image of an American Elm near Lake Marmo from the 1920s.

American elm on Lake Marmo after 1922 relocation with lengthy handwritten commentary on board. Describes moving tree under direction of O.C. Simonds. Note adds tree helped C.E.Godshalk become Arboretum superintendent in May 1922. Drawn illustration of mov

 

If you are interested in learning more about seeds, there are opportunities for you to do so around the Arboretum!

The Sterling Morton Library has a variety of resources that can help you discover more about seeds!

History/Sociology
Enduring seeds : native American agriculture and wild plant conservation by Gary Paul Nabhan
Seeds of adventure : in search of plants by Peter Cox and Peter Hutchison
Seeds of change : five plants that transformed mankind by Henry Hobhouse
Seeds : the definitive guide to growing, history, and lore by Peter H. Loewer
Seeds on ice : Svalbard and the Global Seed Vault by Cary Fowler
Seeds : a natural history by Carolyn Fry
The triumph of seeds : how grains, nuts, kernels, pulses, & pips conquered the plant kingdom and shaped human history by Thor Hanson

 

Ecology
The ecology of seeds by Michael Ferner
Seeing seeds : a journey into the world of seedheads, pods, and fruit by Terri Dunn Chace
Seeds of woody plants in North America by James A. Young
Collecting, processing and germinating seeds of wildland plants by James A. Young


Gardening
Burpee seed starter : a guide to growing flower, vegetable, and herb seeds indoors and outdoors by Maureen Heffernan
Garden flowers from seed by Christopher Lloyd
Growing seeds! : starting from scratch by Linda D. Harris
The new seed-starters handbook by Nancy Bubel
The seed garden : the art and practice of seed saving by Micaela Colley
Starting from seed : the natural gardener's guide to propagating plants by Karan Davis Cutler

 

For kids, during the weekends in September, head to the Children’s Garden from 11am to 4pm to participate in Sensational Seeds, where you can examine seeds up close and learn where they come from.

Additionally, we have an assortment of seed related Children’s Books here at the Library!

The magic school bus plants seeds : a book about how living things grow by Patricia Relf
A seed is sleepy by Dianna Hutts Aston
Seeds of change : planting a path to peace by Jen Cullerton Johnson
Seeds and seedlings by Terry J. Jennings
Seeds sprout! by Mary Dodson Wade

 

References

How many tree species are there in the world? (n.d.). Retrieved from https://www.bgci.org/news-and-events/news/1400/

Fry, C. (2016). Seeds: A natural history. Chicago: The University of Chicago Press.

Milton, K. (2000). Hunter-gatherer diets—a different perspective. The American Journal of Clinical Nutrition, 71(3), 665-667. doi:10.1093/ajcn/71.3.665