Fig. 71.—Twig of the Black Walnut. Note the large chambers in the pith.
Fig. 72.—Twig of the Butternut. Note the small chambers in the pith.
Other characters: The fruit is a large round nut about two inches in diameter, covered with a smooth husk which at first is dull green in color and later turns brown. The husk does not separate into sections. The kernel is edible and produces an oil of commercial value.
The leaves are compound and alternate with 15 to 23 leaflets to each.
Comparisons: The butternut (Juglans cinerea) is another tree that has the pith divided into little chambers, but the little chambers here are shorter than in the black walnut, as may be seen from a comparison of Figs. [71] and [72]. The bark of the butternut is light gray while that of the black walnut is dark. The buds in the butternut are longer than those of the black walnut and are light brown instead of gray in color. The form of the tree is low and spreading as compared with the black walnut. The fruit in the butternut is elongated while that of the black walnut is round. The leaves of the butternut have fewer leaflets and these are lighter in color.