What is the difference between rafflesia and titan arum?

The Rafflesia arnoldii is world's largest bloom.It can grow to be 3 feet across and weigh up to 15 pounds! It is a parasitic plant, with no visible leaves, roots, or stem.

ON THE OTHER HAND....

Amorphophallus titanum, or Titan arum also known as the "corpse flower" is not a single flower. It is a cluster of many tiny flowers, called an inflorescence. The Titan arum has the largest unbranched inflorescence of all flowering plants. The plant can reach heights of 7 to 12 feet and weigh as much as 170 pounds!