The above is Jerusalem-thorn, PARKINSONIA ACULEATA, a member of the Bean Family, just like the mesquites. The curvy things looking like green eel-skeletons are unfurling, compound leaflets. Like the mesquites, Parkinsonia leaves are DOUBLY compound. A short petiole bears one to four PAIRS of leaflets. Well, in truth, sometimes even mesquite leaf-petioles bear two pairs (four leaflets), so, really, the basic structure of the mesquites and Jerusalem-thorn is the same. Pinnae of the Jerusalem-thorn's leaflets, however, are teeny things that fall off as soon as it starts getting a bit dry. If you visit the area during the dry season your Jerusalem-thorns may appear as nothing but naked bouquets of spiny branches.