Juglans cinerea the American Revolution, a butternut extract made from the inner bark of the tree was used in an attempt to prevent smallpox, and to treat dysentery and other stomach and intestinal discomfort. Crushed fruits can be used to poison fish, though the practice is illegal in most jurisdictions. Bruised fruit husks of the closely related black walnut can be used to stun fish. Juglans cinerea Juglans cinerea, commonly known as butternut or white walnut, is a species of walnut native to the eastern United States and southeast Canada. The distribution range of "J. cinerea" extends east to New Brunswick, and
Juglans californica "J. californica" grows in riparian woodlands, either in single species stands or mixed with California's oaks ("Quercus" spp.) and cottonwoods ("Populus fremontii"). "Juglans californica" can be either a large shrub with 1–5 trunks, or a small, single-trunked tree. The main trunk can fork close to the ground, making it look like two trees that have grown together, then diverged. It has thick bark, deeply channeled or furrowed at maturity. It has large, pinnately compound leaves with 11–19 lanceolate leaflets with toothed margins and no hair in the vein angles. It has a small hard nut in a shallowly grooved, thick