These days, this particular vegetable item is easily available with fruit vendor. He sells it raw which look green in color from outside or cooked, which looked black from outside. I like both to eat.
I took the pictures to show the shape here. We feel that the shape resembles urinary bladder and urethra. This tuber grows in water. So applying the knowledge of Doctrine of Signatures, we believe that this tuber may be useful for problems associated with urinary bladder and urethra. We are still researching its usefulness. We may use just the tuber for energy or we may take also the leaf energy to make an 'Energy Remedy' . Then try to learn about its healing property.
Nature communicates with us in many ways. This is one way!