Thanks for the link Virginia.
The description of the leaves of Acacia rorudiana (now Vachellia rorudiana) gave me pause. It said the leaflets are only about 1 mm long, which didn't seem right for the plant in my photograph. But when I took a closer look, I could see that what I took for leaflets were further subdivided, i.e. the leaves are doubly pinnate or compound pinnate, and the primary leaflets do indeed have their own secondary leaflets, which might, in fact, be as small as i mm. Who knew? Thanks for helping me (and others) learn more about this fascinating, if scary plant.
