The black walnut (Juglans nigra) is found throughout eastern North America. Its wood is very popular for making flooring, doors and furniture because it is a tough hardwood. It represents the majority of walnut wood found in North America and almost 2 percent of the total hardwood available in the U.S. market. The sap wood is light, but the hardwood is light to dark brown, sometimes showing purplish streaks.
Called both Persian walnut and English walnut (Juglans regia) is native to Asia, but was later introduced to Europe. This species has the same uses as the black wood, but produces wood that is lighter in color. Native to China, the iron walnut (Juglans sigillata) is mainly cultivated for its nuts, but also produces a hardwood.
Juglans cinerea is the species commonly known as white walnut or butternut. It is native to North America, where it grows about 65 feet tall, producing a light gray bark. Although this species is more valued for its nuts, the soft wood is also used in woodcarving for furniture. Juglans cinerea is an endangered species.
Also called Peruvian, Colombian or Ecuadorian walnut, the Andean walnut (Juglans neotropica) produces a dark hardwood very similar to the black wood. It is native to the tropical areas of South America where its wood is called "nogal" or "cedro negro." Nuts are also edible and the fruit husk produces a sap traditionally used as a dye.