alifornia Walnuts are English walnuts. Their scientific name is Juglans Regia. English walnuts are native to the Middle East. The black walnut is a native American species. Currently the black walnut is used mainly as a rootstock for English walnuts. The meats are tasty but thanks to a very thick shell, they are a lot of work to crack and remove from the shell. Nutritionally speaking black walnuts contain approximately 10% less total fat and approximately 80% less omega 3 fatty acids than English walnuts. According to the USDA Nutrient Database, SR 19, one ounce of black walnuts contains 16.7 grams of total fat and .57 grams of omega 3’s. One ounce of English walnuts contains 18.5 grams of total fat and 2.6 grams of omega 3’s.