Tall tree. Bark with rough, gray, raised ridges over a dark black to gray background. Leaves, large, compound, with leaflets in pairs to either side of center stalk, and, usually a pair of leaflets at the end. Leaflets egg-shaped, pointed. Male and female flowers separate on the tree. Male flowers are green catkins; female flowers are fuzzy green vases with 2 feathers sticking out. Fruits are green, almost spherical. Within this green husk is a dark-staining poisonous, irritating material, and within that, a typical edible walnut.

An important native tree, common in Wildwood, especially in the area around the South Bridge of the Riverway and in the forested area south of the bridge.

Butternut or white walnut (J. cinerea) is very similar, but the bark ridges are shiny, the leaves usually have a single leaflet at the end, and the fruits are oblong and ridged. It is also common around the South Bridge.