Titan arum, corpse flower
The titan arum, the first of two flowers in this list nicknamed the corpse flower, carries the unfortunate designation of being "the worst smelling flower in the world." It smells like — you guessed it — a stinking, rotting corpse. It does its job well enough, since its principal pollinators are flies and beetles that prefer to lay their eggs in dead things. The flower is also clearly titanic, with the largest unbranched inflorescence in the world. This is one massive, smelly bloom. Its vase-like exterior contains thousands of flowers inside, all puffing their fetor into the air. The inside of the spathe is the color of red meat, for added effect. The only good news is that the flower's bloom doesn't last very long, only about 24 to 48 hours, after blooming only once every four to six years.