There were a few of these Prosopis bushes growing in the "ditch" on the south side of Ruta 23. They were close to a patch of Larrea ameghinoi.
There were no flowers on the bushes, but the black seed pods were common. There were one (pictures 1, 4, 5, and 6)) or two pods (pictures 7 and 9), attached tightly to the branch (picture 8). While most of the pods were shiny black, and probably from this growing season, there were a few wrinkled and dry pods (pictures 9 and 10). I think that these are pods from the 2021-2022 growing season that didn't fall off of the plant. Picture 10 shows the fibrous structure of the filling of a pod, after it has dried out.