Black walnut's scientific name is julans nigra, may also be known as eastern black walnut or American black walnut.
Black Walnut
Each year the black walnut tree grows a new annual ring under the bark. This new sapwood is light in colour. At the same time one of the inner rings turns into dark heartwood. This gives the walnut its wonderful contrast between the light sapwood and dark heartwood.
Black walnut is a perfect wood for salad bowls. It is both beautiful and durable. Many of my walnut bowls are solid dark heartwood, while others have a hint of the light sapwood.