Which flowering plant has the world’s largest unbranched inflorescence?

Amorphophallus titanum has the world’s largest unbranched inflorescence.

Often called the titan arum or corpse flower, it is native to the rainforests of western Sumatra, Indonesia. Its enormous flowering structure is technically an inflorescence: a tall spadix covered with many tiny flowers and surrounded by a large, frilly spathe.

The plant’s famous smell resembles rotting meat because it attracts carrion beetles and flies that pollinate it. A flowering can last only a few days, and cultivated plants may take years to bloom. This species is often confused with Rafflesia arnoldii, which has the world’s largest individual flower, not the largest inflorescence.

After flowering, the titan arum usually produces a single huge leaf that can resemble a small tree. The underground corm stores energy for the plant’s unusual reproductive cycle.