I always thought that the largest flower in the world was the Rafflesia until I got these pictures in my email. It seems that the Rafflesia that we have in Malaysia is the largest single flower. The largest unbranched inflorescence in the world is the Amorphophallus titanum. It is a cadaverous flower.It can grow to a towering two meters high and weighs 75 kilos. It blooms for only three days every 40 years.