Sometimes called 'Little Walnut' or 'Texas Black Walnut'. Only grows to 10m tall and has masses of nuts on. The squirrels do not like this one. Ours stay on the tree until winter.
The nuts are about 20mm diameter. The photo compares with a hazelnut. The shell is very hard, with edible kernel inside.
Grows in all soils but prefers slight acid, but does not like shade.
These are supplied 'in the green' when freshly harvested in October, but as the months progress the outer hust is removed.