A legume is a plant in the family Fabaceae, or the fruit or seed of such a plant. Legumes are grown agriculturally primarily for their food grain seed (e.g. beans and lentils, or generally pulse), for livestock forage and silage, and as soil-enhancing green manure. Legumes are notable in that most of them have symbiotic nitrogen-fixing bacteria in structures called root nodules. Well-known legumes include alfalfa, clover, peas, beans, lentils, lupins, mesquite, carob, soybeans, and peanuts. Locust trees (Gleditsia or Robinia), wisteria, and the Kentucky coffeetree (Gymnocladus dioicus) are also legumes. A legume fruit is a simple dry fruit that develops from a simple carpel and usually dehisces (opens along a seam) on two sides. A common name for this type of fruit is a pod, although the term 'pod' is also applied to a few other fruit types, such as vanilla and radish.