Walnuts (genus Juglans) are plants in the family Juglandaceae. They are deciduous trees, 10–40 meters tall (about 30–130 ft), with pinnate leaves 200–900 millimetres long (7–35 in), with 5–25 leaflets; the shoots have chambered pith, a character shared with the wingnuts (Pterocarya), but not the hickories (Carya) in the same family.
Food features:The word walnut derives from Old English wealhhnutu, literally "foreign nut", wealh meaning "foreign" (wealh is akin to the terms Welsh and Vlach; see Walha and History of the term Vlach).The walnut was so called because it was introduced from Gaul and Italy. The Latin name for the walnut was nux Gallica, "Gallic nut".
Place of origin:The 21 species in the genus range across the north temperate Old World from southeast Europe east to Japan, and more widely in the New World from southeast Canada west to California and south to Argentina. The Latin name, Juglans, derives from Jupiter glans, "Jupiter's acorn": figuratively, a nut fit for a god.
Dietotherapy function:Walnuts are considered to be a herb in Traditional Chinese medicine. They are said to tonify kidneys, strengthen the back and knees, warm and hold qi in lungs and help kidneys to grasp the qi, moisten the intestines and move stool. It is believed to stop asthma and is prescribed to be taken between bouts of asthma, but not for acute asthma. It is also used by the elderly to relieve constipation.