Susan Nickerson, age 13, of Costa Mesa, California, for her question:
What are water chestnuts?
True chestnuts grow on large spreading trees that live with their roots deeply anchored in the solid ground. Water chestnuts as the name implies, make their home in water ‑‑ and they are not at all related to the spreading chestnut tree.
The native home of the water chestnut is southern China, but it has been coaxed to grow in many warmish parts of the world. Some years ago, a few plants were introduced to our Potomac River and they did so well that their thriving foliage clogged up the sluggish inlets along the shores. They became a terrible nuisance to boaters and mats of the thick green vegetation had to be removed from the river.
Like water lilies and lotuses, the water chestnut plant is specially adapted for an almost submerged aquatic life. Its thick underwater stems are spongy with air pockets. It has submerged leaves that are divided into feathery green fringes. Another set of leaves is specially grown to float like lily pads on the surface. The plant enjoys life in stagnant water or rather sluggish streams, and every year it produces a quota of blossoms that ripen into nutlike fruit. The milky‑white flowers sit on the water like four‑pointed stars about one inch wide.
The seed‑bearing fruit that develops from the blossom is in four sections, each pointing outward with a long, curved spine. The squarish nut with a spike at each corner somewhat resembles the caltrop, a sneaky little weapon that ancient warriors tossed on the ground to clog the hooves of their enemy's horses. At one time, water chestnuts were called water caltrops and the "caltrop" may have been changed later to "chestnut." In any case, we do not know how long ago the ancient Chinese first waded out to gather the spikey nuts and' dared to sample them. This must have been ages ago because water chestnuts have been important ingredients in Chinese recipes for countless centuries.
Nowadays, the plants are cultivated as vegetable crops in Formosa and very many other warm wet parts of Asia. The largest water chestnut territory is around the Yangtze River of China, where the plants thrive in the lazy streams and stagnant back waters of the area. At harvest time the nuts are gathered and shelled and large quantities are canned to be shipped around the world. The crunchy white nutmeat is rich in carbohydrates and all of us have enjoyed munching on the slivers of water chestnuts in chow mein and other Chinese recipes.
The plant world provides us with hundreds of edible nuts. Several varieties introduced to us from distant lands have bewildering and confusing names. The water chestnut may be confused with the Chinese waternut, though the two are unrelated. The waternut is a type of sedge plant and not truly aquatic. The botanical name of the true water chestnut is Trapa natans, and we know from experience that this tasty specids can be coxcd to grow in at least one of our rivers.