Other plants that smell like rotting flesh to attract pollinators include the Dragon Arum (Dracunculus vulgaris), which has a burgundy leaf-like flower out of which flows a slender, black appendage. The plant is found in the Mediterranean.
"A related plant is the infamous Amorphophalus whose name relates to the rather suggestive shape of the erect black spadixliterally shapeless penis," said Halligan. "However, all these plants which we consider freaks are only freaks because we cannot see any attraction to carrion ourselves."
Douglas Justice, the associate director and curator of collections at the University of British Columbia Botanical Garden and Centre for Plant Research in Vancouver, Canada, said he is not sure what motivates people to grow plants that smell bad. He prefers the ones that smell good.
"These generally make people smile, particularly when they're surprised by the source, the specific aroma, or its power," he said.
Among Justice's favorite smelling plants include the sweet-smelling leaf undersides of the rhododendrons Rhododendron traillianum and Rhododendron wasonii. He also likes the smell of white chocolate from the small Chilean tree Azra microphylla.
Halligan said her personal favorite weird plants are those with black flowers, such as the black hollyhock (Alcea rosea,) which has double blooms of deep maroon-black on tall stems.
"[Black flowers] seem to rebel against nature and draw us to their nonconformity," she said. "In this respect they are perhaps the rock stars of the plant world."
According to Harper, plants evolve their seemingly strange shapes, sizes, smells, and actions for one simple reason: procreation. "Competition is stiff among plants. Everyone is trying to get a piece of the pie," he said.
Justice is less certain as to why plants, including the weird ones, look the way they do, but he likes to speculate. One of his favorite weirdoes is the fierce Spaniard (Aciphylla horrida), which is a member of the carrot family and can be found in New Zealand.
"[It] has leaves shaped like long swordsvery stiff and extremely sharp. This is pretty cool in itself, but the flowers are surrounded by similarly ferocious bracts," he said. "Obviously this is a defense against grazing animals picking off the tender bits of the plant, but considering that there are no native grazers, the defense probably evolved to protect the flowers from birds, probably really big birds, like the moa (Dinornithidae)."
Another favorite curiosity for Justice is Harpochloa falx, a small southern Africa grass species that looks like nothing special until one gets up close and realizes it has a chain of upside-down flowers growing off the tips. Most grasses are wind pollinated plants, but Justice speculates that Harpochloa might be adapted to brushing pollen onto passing animals.
"Such plants make me smile and make me want to show other people so that they'll smile," he said.
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