Corriewf said:Problem is that black walnut leaves can alternate too..
Here you need to be very careful when differentiating with the word "alternate".... the word alternate has different meanings for compound leaves vs simple leaves.
Black walnut has alternate compound leaves. See the image below:
Within each compound leaf-set, each simple leaf of a black walnut tree will not alternate along the stem. However each leaf-set or compound leaf does alternate along the main branch.
Source: (broken link removed to http://www.uwgb.edu/biodiversity/herbarium/trees/alternate_opposite_leaves01.htm)