Species: Juglans Regia
A walnut is the nut of any tree of the genus Juglans (Family Juglandaceae), particularly the Persian or English walnut, Juglans regia. It is used for food after being processed while green for pickled walnuts or after full ripening for its nutmeat. Juglans regia, the Persian walnut, English walnut, especially in Great Britain, common walnut, or especially in the US, California walnut, is an Old World walnut tree species native to the region stretching from the Balkans eastward to the Himalayas and southwest China.
Walnut husks can be used to make a durable ink for writing and drawing. Walnut husk pigments are used as a brown dye for fabric.