Why Did Plants Evolve These Weird and Horrific Flowers?

Most people don't have very strong feelings about flowers, unless they are incredibly beautiful or smell really good. But it turns out that flowers represent a major technological advance for plants, and evolution has generated some pretty unimaginably weird specimens.

Prior to the evolution of flowers, plant reproduction was a little…hit or miss. Lots of plants relied on the wind to carry their pollen to another plant, while relatively few used insects to carry their pollen from one plant to another. Sometime in the Cretaceous, a mutation evolved that generated clusters of leaves in a flower-like arrangement. Since then, these plant sex-organs have been evolving at a rapid clip to enhance the efficacy of reproduction. Flowers can attract animals and insects, facilitate the transfer of sperm within a single flower (self-pollination…everyone does it!), or generate seeds without the addition of any sperm at all. Some of these developments have led to downright bizarre flowers, often appearing so alien as hardly be identifiable as part of a plant. Take, for instance:

The Passionflower

Why Did Plants Evolve These Weird and Horrific Flowers?

There are about 500 species of passionflower , and their uniquely shaped flowers have evolved to exploit almost every possible reproductive strategy. Primarily, these plants rely on large-bodied pollinators, like bees and hummingbirds, but some species prefer to self-pollinate. These strange flowers can have hundreds of wavy filaments, striking blue and white colors, and some even exhibit protocarnivorous behavior (meaning they don't digest insects themselves, but rather, rely on other bacteria to do it for them). One species, Passiflora mixta, has a very elongated flower, and relies on the sword-billed hummingbird for pollination, the only species with a bill longer than its own body.

The Black Bat Flower

Why Did Plants Evolve These Weird and Horrific Flowers?

This tropical plant (Tacca chantrieri) puts on a spectacular display, but black flowers are relatively rare in nature. Scientists had hypothesized that these fringed, drooping black blooms mimicked rotting vegetation, and thus attracted flies, their main pollinator. Nothing like mimicking rotten garbage to attract a suitor! As it turns out, when scientists actually looked at the rates of pollination by flies, the plant wasn't so much into having flies dance all over its sexy parts. Instead, the plant consistently and successfully self-pollinated. At present, it isn't clear what purpose these crazy flowers serve, and they may just be a left-over relic from when the bat flower was really into flies.

The Sea Poison Tree

Why Did Plants Evolve These Weird and Horrific Flowers?

This tree (Barringtonia asiatica), as you might guess, is poisonous. This little gem produces enough poison that it is commonly used to stun fish for harvest in freshwater streams. Although it has a dirty little homicidal secret, it produces an absolutely stunning flower. This pink and white puff-ball of a flower is specially evolved to attract night-fliers like bats and moths. It produces a heavy scent and copious nectar. When bats and moths stick their faces in the flower for a tasty treat, they are showered with pollen by all of those fringy stamens.

Skunk Cabbage

Why Did Plants Evolve These Weird and Horrific Flowers?

Sometimes, words paint a picture. Quick, cover up the photo, get out a crayon and draw a skunk cabbage (Symplocarpus foetidus) flower. Is it ugly? Does it smell bad? You pretty much nailed it. But in addition to being ugly and stinky, this plant has some magical powers. This flower, as you might guess, relies on flies and other stink-oriented insects for pollination. In order to call in flies from far and wide, this plant employs a pretty unique trick…it can generate heat. This flower, which emerges very early in the spring, can warm the air nearby to temperatures that melt snow and ice, making it the first little blotch of (horrible rotten meat) color in the spring. This warmth may also help the plant spread its stench long distances.

Elephant Foot Yam

Why Did Plants Evolve These Weird and Horrific Flowers?

Turns out, this whole "smell like rot" thing is a good strategy when you are a flower. Many people have probably heard of the corpse flower (Amorphophallus titanum), the giant, stinky flower that blooms very occasionally (about once every 10 years). But other plants utilize the smell of rot and the appearance of raw meat to attract beetles and flies. The elephant foot yam (Amorphophallus paeoniifolius) is perhaps the weirdest looking. It has a fleshy, wrinkled spadix at the top, a characteristic of this type of plant, and a red brown flower petal surrounding it. Like other members of the family, this plant produces a fleshy tuber which is actually grown as a food-crop around the globe.

The Alien Orchid

Why Did Plants Evolve These Weird and Horrific Flowers?

Orchids, generally speaking, have some pretty complex flowers. These can range from large and colorful, to small and clear. But Dendrobium spectabile has probably the most unusual. These petals of these plants are incredibly twisted and crumpled, sometimes causing the flowers to be unable to open. This weird twisting is actually an adaptation to preventing flying insects from accessing the pollen of the plant. Some insects steal pollen without fertilizing the flower, which can be very costly, from the plants point of view. The alien orchid has thwarted flying insects, and evolved a unique hinged access to its pollen, which only invites in specific crawling insects.

Parachute Flowers

Why Did Plants Evolve These Weird and Horrific Flowers?

These flowers look like something straight out of sci-fi. If you saw these on a new planet, you might back away a bit, and for good cause. It's a trap. Well, a temporary one. These flowers first attract their main pollinator, flies, with a good wiff of stench (again). Attracted by the smell of exquisitely rotted meat, flies are then lured inside the flower by a string of downward-facing hairs. Once inside the flower structure, the flies are coated with pollen and eventually wander out, dazed and confused, and ready to fly off to the next banquet/trap.

Stanhopea Orchids

Why Did Plants Evolve These Weird and Horrific Flowers?

This genus of orchids is noted for its colorful, twisted, heavily scented flowers. Growing in damp forests in Central and South America, these plants create large displays of hanging flowers. Unlike many flowers, which rely on visual cues to lure in pollinators, these flowers use their rich perfume to attract orchid bees, which are large, heavy bodied bees that use plant fragrances to mark territory and create mating displays (like wearing Axe body spray, except not horrible). These lovely perfumes are sequestered deep within the twisted flower, and bees have to expend quite a bit of effort to get to them. In the process, bees typically end up sliding backwards out of the flower, and bumping into a little sack of pollen, which sticks to the bee's back. When the bee visits the next flower to freshen up its perfume, it repeats the sliding routine, depositing pollen in the new flower.

Flowers go way beyond your standard roses and tulips. In an effort to enhance reproduction, plants have evolved colorful, large, and heavily scented flowers that are highly functional, attracting the right pollinators at the right time, or thwarting insects that might rob them of their pollen. This need to successfully reproduce has generated some truly incredible plant structures.

All photos via Wikimedia Commons