Experts at the Niagara Parks Floral Showhouse say one specimen of the rare Amorphophallus titanum has opened.
But they say the bell-shaped plant won't last long and its centre spike has already started to droop.
By Sunday, it will likely have turned into a "tree-like stalk."
Experts say the unusual flower, whose name means "misshapen phallus," has bloomed in a botanical garden only 21 times.
The plant _ considered the tallest flower species in the world _ gives off a unique smell most often compared to rotting meat.
Parks staff say a second flower is expected to bloom in the coming weeks.
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