United States Finally May Have a Vegetable It Can Call Its Own : Food: Archeologists have discovered a small, wild gourd that they believe is the ancestor of today’s summer squashes.
Turkey is tasty, but Thanksgiving Day would be unthinkable without pumpkin pie, mashed potatoes, creamed onions, sliced carrots, buttered beans, baked squash, apple dumplings and other mouth-watering recipes of the season. Yet, traced back to their beginnings as food crops, precious few of these fruits and vegetables are known to have originated in North America.
Pumpkins, for instance, were probably first domesticated some 8,000 years ago in Mexico. Potatoes and tomatoes come from South America. Onions come from India and China, and carrots are native to Afghanistan.
Following a recent discovery in the Ozark Highlands of Arkansas and Missouri, the United States finally may have a vegetable it can call its own: squash. Searching the banks of isolated Ozark rivers and streams, Smithsonian archeologist Bruce Smith and archeologist C. Wesley Cowan, of the Cincinnati Museum of Natural History, discovered a small, wild gourd that they believe is the ancestor of today’s many varieties of summer squashes.
“American Indians living in eastern North America first cultivated this gourd ( Cucurbita pepo ozarkana ) more than 3,000 years ago, long before any domesticated plants were introduced from other areas,” Cowan said. “It is the fourth-known prehistoric plant to have been domesticated in North America and is important new evidence that eastern North America was one of the world’s independent centers of plant domestication and agricultural development.”
Nicknamed the “Johnny gourd” in western Kentucky, Cucurbita pepo ozarkana resembles a chicken’s egg in color, size and shape, although some varieties are pear shaped or have green and white stripes. Farmers in western Kentucky have known for decades that it grows in fence rows and encroaches on corn and soybean fields.
“This gourd has been hiding in plain sight from scientists for 150 years,” Smith said. “Because of a belief that this gourd was a ‘garden escape,’ botanists and others have not considered it worthy of much interest.” Garden escapes are crop plants that have spread outside the fields and gardens where they were planted, establishing wild populations.
Longstanding theories of the gourd being an “escape” were called into question after Smith and Cowan found it thriving far from human civilization in the Ozark Highlands. “In almost every stream or river we investigated, we found wild gourd vines climbing up into trees and bushes or stretching across gravel bar,” Smith said.
Circumstances surrounding the “rediscovery” of the Ozark wild gourd lend credence to theories that eastern North America was once a center of plant domestication, a controversial point debated by archeologists for more than 60 years. Three other plants domesticated by Indians in this region are the sunflower, marsh elder (a coarse, shrubby plant common in moist areas) and goosefoot (a weedy, deep-rooted perennial with edible spinach-like leaves; lamb’s-quarters is one of the most common species).
The human transition from hunting and gathering to agriculture was one of the major ecological changes in the history of the planet, said Smith, who works in the anthropology department of the National Museum of Natural History in Washington, D.C. “Agriculture was discovered at different times in different parts of the world, yet eastern North America has never been recognized as one of these places. It has long been assumed that the Indians living in the region that is now the eastern United States sat around passively, waiting for others to send them the gift of agriculture.”
Credit for the domestication of most food crops in the Americas has been given primarily to Mexico and South America. Because Mexico is home to many wild varieties of cucurbits--pumpkins and squashes--the tremendous diversity of modern squashes and ornamental gourds was thought to have originated there.
According to traditional theory, Indians living in Mexico first collected gourds and planted their seeds for food roughly 8,000 years ago. Cucurbit seeds and knowledge of how to grow them passed from group to group of prehistoric Indians, eventually reaching and spreading throughout North America. In the late 1960s and early ‘70s, discoveries of cucurbit seeds and rinds--nearly 8,000 years old--in Mexican caves strengthened beliefs that all squashes and gourds originated in Mexico.
However, during excavations in Illinois, Missouri, Kentucky and Tennessee in the 1980s, archeologists recovered rinds and seeds of wild gourds from Native American camp and village sites that date back 7,000 years. Although the gourds were clearly being eaten, perhaps as a trail snack by Native Americans, these leftovers showed no evidence of domestication. Gourd fragments recovered from later sites--3,000 to 4,000 years old--did show signs of domestication.
“When humans intervened in the life cycle of this plant by collecting and planting its seeds for an extended time, the seeds became bigger and the rind got fleshier,” Smith said. “These are morphological changes we can recognize even though the seeds and rinds may be thousands of years old.”
Along with several other researchers, Smith and Cowan began to question the theory that cucurbits were introduced to eastern North America as domestic plants. If they traveled from Mexico as a food crop, why didn’t the 7,000-year-old gourd seeds show signs of cultivation? If not introduced as a cultivar, then perhaps it was a native plant.
In the fall of 1990, Smith and Cowan launched an expedition into the remote streams and rivers of the Ozark Highlands to search for a wild gourd that might be the ancestor of today’s summer squashes.
Cowan and Smith studied the life cycle and environment of gourds found on their expedition and determined that they were not “garden escapes,” but wild plants long adapted to river flood-plain life. Dispersed by flood waters each spring, the small, buoyant gourds each contain 100 to 200 seeds. The seeds, which are 25% protein, would have made an excellent (but bitter-tasting) food for Indians in eastern North America, Smith said.
“Based on our habitat studies, Cucurbita pepo ozarkana is a wild, indigenous plant. It would seem difficult to continue to dismiss it as a garden escape,” Cowan said.
Smith and Cowan collected gourds from 20 different locations along the Gasconade River in Missouri and the White and Buffalo rivers in Arkansas and turned them over to Dr. Deena Decker-Walters and Dr. Terrence Walters, authorities on the taxonomy and evolution of the squashes at the Fairchild Tropical Garden in Miami. The team conducted a detailed genetic analysis of the Ozark wild gourd, comparing it to other wild gourds and with a wide range of domesticated pumpkins and squashes from the family Cucurbita pepo .
“The Ozark wild gourd possesses the genetic pattern that we would expect for the wild ancestor of the eastern North American squashes,” Decker-Walters said. Their findings confirmed that these gourds are indeed wild and unlike any other wild gourd known to science.
“It is this wild gourd that Native American people of the eastern United States developed some 4,000 to 3,000 years ago into the many varieties of domesticated squashes we know today,” Cowan said.
“The Ozark wild gourd has been crossbred, hybridized, fiddled with in Europe and North America and other places around the world, resulting in the wide variety of summer squashes and ornamental gourds we have today--acorn, crookneck, zucchini, summer squash, ornamental gourds and others,” Smith said. Pumpkins, Smith added, originated from a wild Mexican gourd that is still unknown.
Archeological and biological evidence surrounding the discovery of the Ozark wild gourd might prompt many archeologists to re-evaluate theories on the development of agriculture in eastern North America, Cowan said.
“This gourd is one element in a growing body of evidence that agriculture developed independently in eastern North America, through the cultivation of indigenous plants,” Cowan said. “Theories that domesticated plants and the techniques to grow them were introduced from outside are no longer viable.”