Comon names can often lead to confusion, particularly when a tree has more then one comon name or when one area of the country calls it one name and another calles it something else. With walnut it is more confusing because there are more then one species called by the same common name.
In the eastern and midwest part of the US the most comon type of walnut is julgans nigra, comonly known as either american walnut or black walnut. In california we have two types of native walnut, juglans hindsi and juglans californica. as you can guess the comon name for the one is california walnut. it is native to the southern part of the state is actualy a poor excuse for a tree and is more shrub like with multiple small trunks. Juglans hindsi is comonly called clao walnut but is also sometimes called california walnut or black walnut. I hope you are now starting to see where the confusion with comon names can lead you.
Now throw in a little juglans regia which is usualy comonly known as english walnut but came from Italy where it was known as carpathian walnut and before that it was imported from the middle east and is also know as persian walnut.
You may think this is all just a bunch of word games but I am guessing if you wanted to buy some black walnut to match the wood you used on the first half of a large project you would want it to match in color and grain and knowing the correcty name for what you have can avoid errors.
So to answer the original question is it walnut of black walnut? It is both but which type should have been the question. Judging from the location of the poster I would venture a guess that it is juglans nigra, but without proper id on the tree that is just a guess.
Your right it was beautiful!! Hope we have more days like today coming!! Keep up the
