Conservation Guardians of Northwest Illinois
Apios americana, commonly known as groundnut, is a native species that served as a food staple for indigenous peoples. Native Americans (and some
colonizing Europeans) scratched the earth for its tubers and did so with good reason, for not only are the roots
palatable (Thoreau likened the taste to that of a sweet, frost-bitten potato) but
they are nutritious with a protein content of over 15 percent (compared to
the potato's two percent).
A. americana was quasi-farmed by Native Americans and could yet be farmed again if modern feasibility studies examining its potential as a crop species pan out. Even if they don't, A. americana will remain a coveted plant for its attractive and mechanically inclined flowers.
When the proper insect explores a groundnut flower, it triggers the style housed inside the front horn-like petal, called the "keel," to snap downward, exposing both stamens and stigma. The stamens dust the insect with their pollen while any pollen already present can be transferred to the stigma.
Biologists can assess likely fertilization by counting triggered flowers since only true pollinators seem to be able to "trip the keel." However, this intricate mechanism is apparently unnecessary since A. americana plants rarely produce seed.
One recent study found that only ten percent of wild A. americana flowers tripped, and of those only half set seed. Groundnut reproduces primarily by spreading underground roots. This specimen is part of a colony of groundnuts growing near a lake a few hundred yards from the Mississippi River in upper eastern Iowa.
"The Squaw laid a skin for me, and bid me sit down, and gave me some ground-nuts, and bid me come again..."
— Mary Rowlandson, Narrative of the captivity and removes of Mrs. Mary Rowlandson, 1774.
— Richard Pearce
Groundnuts, photography by Richard Pearce
Thoreau, a celebrated fan