A-Nature Blog

Pipevine is a South Texas native that produces an unusual flower with a black and white “flag” to attract flies. It has a musky odor that resembles rotting flesh. Tess Thornton photo.

The Special Allure of Brown Flowers – Spring wildflowers come in a gorgeous array of colors:  Yellow, red, pink, white, purple and blue.  There are even a few greenish hued ones, like Pearl Milkweed.  But brown is not a color you usually associate with flowers.

Still there are a few plants whose blooms are such a deep, brownish red or dark maroon that we can’t really call them anything but brown!

One of our South Texas wildflowers, the Swanflower, is a good example.  It gets its name from its intriguing tubular-shaped flowers that have a three-inch long curved neck that resembles a swan’s neck.  Each flower has a “flag” at the head end.  This flag is black with white spots, or as one source says “the calyx is brown-purple.”  But it looks black to me!  Another common name for this plant is Pipevine (Aristolochia erecta) indicating that it is in the same family as Dutchman’s Pipe.  Indeed, Dutchman’s Pipe’s flowers resemble those long, pot-bellied pipes that were used to smoke tobacco in Holland.

Why such an odd shape and so dark a color?  To attract pollinators of course!  Pipevine (and Dutchman’s Pipe) produce “a variety of unpleasant scents, mostly mimicking carrion.  Rotting meat attracts flies and flies are the main pollinators of these plants.”  If you think about it, the color also is that of putrifying flesh.  So with appearance and “fragrance” these plants pull in their pollinators.  The flies crawl down the long narrow neck of the flower searching for the object of their desires, only to be duped.  Once they have reached the stamens and pistil in the base of the flower and have not found the proffered carrion, the flies try to crawl back out the neck.  They cannot.  They are trapped by the stiff, downward-facing hairs lining the throat of the flower.  And to make the trap even more secure, the flag of the flower’s top wilts and covers over the opening.  The fly can only wander around inside the trap, transferring pollen to the pistil as it goes.  Perhaps, once pollination is completed, the stiff hairs wilt too, and the fly can escape…only to be attracted by another whiff of faux carrion!

Another South Texas wildflower is the succulent known as Spice Lily or Texas Tuberose (Manfreda maculosa).  Its flowers change from greenish-white to deep maroon.  Its leaves are spotted with chocolate brown splotches.  However, I have not noticed an unpleasant smell around its blossoms.  A carrion odor is not needed to attract the moths that pollinate it.   Another Manfreda (possibly Manfreda virginica or a hybrid with M. maculosa) has a 6-foot bloom stalk with dozens of truly brown flowers.  Large moths, like the Sphinx moths, readily pollinate this Manfreda when they brush against the long, exserted stamens.

Other brown flowers occur around the world.  A pretty, little thing, the Chocolate Lily, is native to the Pacific Northwest.  It has “bowl-shaped, distinctly nodding flowers with six tepals which are brown–mottled with green or yellow.”  It is brown but it lacks the foul smell that so many of these dark flowers have.

Owl’s Eyes is an easy-to-grow succulent that is also called Carrion Cactus Flower. Can you guess why? Wikimedia Commons photo.

Owl’s Eyes (Stapelia sp.) are easy-to-grow succulents that are sometimes called Cactus Carrion Flowers.  By now, I bet you can figure out why!

Then there is the incredible Carrion Flower:  This giant has the world’s largest flowering head with a spadix (central column) reaching nine feet.  It is red-brown in color and stinks like (you guessed it) carrion.  The Daily Mail (December 22, 2008) wrote “You would think that a flower that resembles a 3-metre phallus would have no trouble attracting attention, especially if it also smells like a rotting corpse.  But for the carrion flower…getting noticed by flesh-eating insect pollinators in its jungle home, requires yet another amazing adaptation—one that only came to light through a serendipitous TV recording.”  A TV crew was filming the giant flower in an arboretum in Bonn, Germany when they noticed what appeared to be smoke coming out of the top of the spadix.  The smoke (actually water vapor) was “puffed out in regular pulses, coinciding with waves of carrion scent.”  It was a fascinating discovery:  cyclical odor production.  Another discovery was yet to come:  the flower produces heat!  William Barthlott of the University of Bonn hypothesized that the giant flower “uses heat to pump out hot clouds of stench into the night sky.”  Infrared cameras proved this to be correct:  “waves of heat traveled up the flower until the tip reaches an impressive 36 C” (almost human body temperature), and vapor is released.

The brown flowers of this Manfreda have long stamens to brush up against moths that come in to pollinate it. Karen Benson photo.

The Carrion Flower, also known as the Titan Arum, is a huge flower that grows in the jungles of Sumatra. It mimics carrion with its brownish-red color, smell, and even heat! Wikimedia Commons photo.

Carrion-scented flowers have been known to get hot.  The generation of heat seems to be yet another adaptation of these odd plants to mimic carrion.  Anyone who has ever made compost knows that decaying matter will produce heat.

I don’t know if the Swanflower, the Manfredas, or the Owl’s Eyes also produce heat, but it would not be too hard to find out.

Have I piqued your interest in some odd plants?  Maybe you would like to acquire some and investigate them further.   Some of these brown-flowered plants will be for sale at the upcoming Beeville Garden Club Botanical Sale to be held on Saturday, April 28th, 2018 at 178 Fairway Ridge.  Come shop from 9AM until Noon and get some of nature’s oddest plants!

04/13/2018 – Column by Karen L. P. Benson