Legumes are plants in the pea family that produce pods that dehisce, meaning that they split open naturally along a seam, revealing a neat row of seeds. They are cultivated for both human and animal food, in addition to being grown as ornamentals. The plants can be found growing on every continent, demonstrating the adaptability of the over 18,000 species. Most people eat legumes regularly, and the plants are quite common as well.
The defining feature of legumes is the pods, which can vary in size and length, depending on the plant. When allowed to grow naturally, the pods will split open as they dry out, releasing the seeds and allowing the plant to spread. Some pods even pop open almost explosively, projecting the seeds to cover the area more widely.
Humans have been growing and eating legumes for a very long time, with archaeological evidence suggesting that they may be the oldest crop known to man. Many plants in this family were probably naturally edible before domestication, while others developed more plentiful, large seeds as a result of being grown by humans. Some well known types include beans, peas, peanuts, lentils, and alfalfa, among many others. In addition to having edible seeds, some plants also have useful foliage that can be used to feed animals; others are planted as forage crops for creatures like cattle.
When dried, legumes are known as pulses. Pulses are famous for being able to endure extended periods of storage, making them a very useful food to grow because they can be eaten during lean periods. The seeds are also very high in protein, making them an excellent addition to the human diet, and many have a rich assortment of vitamins and minerals as well. Because of their nutritional value, they play a very important role in the diets of the world's poor, and they are quite popular with wealthier individuals as well.
Legumes are also good for the soil. They are adept nitrogen fixers, meaning that they pull nitrogen from the atmosphere into the soil; this trait can help to restore soil that has been depleted of nitrogen by other crops. The plants are therefore often included in crop rotation, and sometimes planted along with various vegetables to ensure that the soil will not be stripped of its useful nitrogen.