I have a vine with fragrant small white flowers on it that produces a green spiny seed pod (about 2 inches long, 1 inch + across and oval). The seed pods fall off the vine, which is on the shared fence with the neighbours) and the ends split open to reveal dark brown/black seeds. What could it be? I am most concerned that it is not poisonous as I have dogs roaming the yars just looking for trouble. Thanks!