Pith is buff-colored and chambered after the first season. Bark is brown and furrowed. The butternut is known as white walnut in the south and is a smaller tree than the black walnut, although it may reach a height of 70 feet with a diameter of 3 feet. The trunk is usually forked, or crooked, making it less desirable for saw timber. Butternut is normally found in a more mesic site than is black walnut, such as above the floodplain along a slope.
Winter buds have few scales.
Mature bark is deeply fissured. This tree may also be distinguished from black walnut by the velvet collars just above the leaf scars left by the previous year's leaves. Pith is dark brown in color, chambered after the first season, and a good identification characteristic. The black walnut has more leaflets than the butternut on average. The flowers are of two kinds and on the same tree.