- The seeds of the oldest documented leguminous plant, Lens culinaris or L. esculenta, originating in the Middle East but now common throughout the world. They are about 5 mm in diameter and usually dehusked and split in two. Red, green and brown (orange when dehusked) varieties exist, the latter keeping their shape on cooking. None require soaking prior to cooking. Other seeds are incorrectly called lentils, e.g. black lentil (black gram) and green lentil (mung bean).