It's a treat for a botanist's eyes, but definitely not the nose. The rare "amorphophallus titanum" or corpse flower, is in bloom at the U.S. Botanic Garden. The flower, also known as the "titan arum," began to bloom Saturday (November 19). Once these flowers fully open, they remain in bloom for 24 to 48 hours, then collapse quickly. The renown of the titan arum comes from its great size. It's reputed to have the largest known un-branched flower. The corpse flower stores energy in a huge underground stem called a corm. The plant blooms when enough energy has been accumulated, which usually takes several years. The arum at the U.S. Botanic Garden measures 4 feet tall and its stem weighs more than 100 pounds. The average height of a bloom is about five feet. The largest one in cultivation was 9 feet, 2 inches, but in their natural habitat, these arums can grow up to 12 feet tall. At full bloom, the plant is well known for smelling like rotting meat, hence the name "corpse flower." The odour is released in pulses and attracts carrion beetles and other pollinators. The titan arum is native to the tropical rainforests of Sumatra, Indonesia. Since the first recorded bloom in the U.S. in 1937, titan arums have been exhibited in this country on just a few occasions.