Picture a flower now, in your head. What do you see? Say it out loud even, or describe it in your mind (or in the comments below before reading on- honor system, I trust you).
Picture a flower now, in your head. What do you see? Say it out loud even, or describe it in your mind (or in the comments below before reading on- honor system, I trust you).
Likely you pictured something colorful, perhaps with petals and a thing in the center containing male & female reproductive structures.
Flowers, however, are diverse in form, time of appearance, and reproductive strategy.
An Extreme of Floral Diversity
Hearing that word, “diverse”, doesn’t really convey the idea that there are 350,000 flowering plants known to exist on Earth (and ~2,000 new ones were discovered last year). All are variations on a theme, designed to generate the next generation of plants.
One way to convey flowering plant (angiosperms if you want to be technical) diversity is to consider one that is bizarre, rare, and seemingly alien (though very much of this Earth). With 350,000 to choose from, there are many flowering plants that might meet that description, but one just bloomed in the greenhouse above the lab where I work. It is even rare in its native range on the mountainsides of the Sumatran rain forest. It could easily be considered alien (to be clear, again, it is of this Earth).
What is this plant?
It is Amorphophallus titanum, or the Titan arum (technically, it’s an inflorescence, but functions as a single flower). “Morphy” (#TeamMorphy) bloomed past weekend at the Dartmouth greenhouse (and ~3,000 visitors passed through to see and smell Morphy this past weekend).
David Attenborough got to meet one in its natural environment for his series The Private Life of Plants. It seems even eerier in its native environment.
2016 has been a bumper year (see also here) for Titan arum flowering, with many botanical gardens having titan arum blooms this year. They are known colloquially as “corpse flowers” because the odor they produce to attract pollinator(s?) that would normally go for animal carcasses. Some might consider so many titan arums blooming a bad omen of some kind.
How the Giant Flower Works
The flower tricks these carrion-loving insects into pollinating it. The flower lasts for a mere 2 days before wilting and leaving behind a ring of fruits, each containing 2 seeds. Even the seed/fruit structure of the plant looks alien.
After the flower wilts, the underground tuber (or corm)- sort of a giant potato (Morphy’s tuber weighs 37-40lbs, 16.7-18.1kg, they can be up to 70kg)– will eventually sprout a leaf that can be 7m (22 feet) tall and looks like a tree (a small leaf can be seen to the right of Morphy in the slide slow above). Eventually- usually after 3-10 years, it might bloom again. Below are the reproductive parts of the flower, the fully open flower from above, and Morphy starting to wilt:
As if looks and smell aren’t enough, many plants in the arum family, including the titan arum, can heat themselves up by expending a lot of energy. Specifically, the spadix, the tallest part of the flower, the large, central, cone-structure in the middle, is what heats up to almost human body temperature– 93.2F, 34C. Why would a tropical plant produce its own heat? Titan Arums live at a slight elevation (400-1200ft, 120-360m above sea level) in Sumatra where it may be cooler. Their pollinators are also most active during the night (& is when heat production in the plant is observed when it would also be a bit cooler).
Not only does it heat up for its brief opening state, but waves of heat move up the spadix. There is evidence that these waves of heat help the titan arum spread it’s scent of rotting meat further by creating convection currents in the air to waft its scent for miles around, ideally brining pollinators from another corpse flower bearing pollen. Though not tested as yet, the heat may also be part of the mimicking carrion, further attracting pollinators.
On average, the first night of a mature corpse flower, the female flower parts- the stigmas– mature first, when the scent production is strongest. Luring pollinators might be good, but there’s no mature pollen to collect at first, so a mature corpse flower hopes that pollen from a slightly further along corpse flower has lingering insects that will collect pollen on their way out from the diminishing corpse mimicry of a titan arum on its 2nd night in bloom (where the pollen generating area specifically generates heat) and move onto one earlier in development. Pollinators may well follow the strongest odor.
This near-hopscotch dance seems crazy, and another thing that makes these flowers seem alien is that pollination works at all. That is true of any flower, really. That pollination by insects was such a successful evolutionary strategy it has led to much of the diversity of flowering plants, the plants we inevitably see every time we are looking at the green world, is remarkable ((flowers do use all sorts of pollination strategies too– wind, insect, bird, bat, flinging, etc.).
If you have the chance to see a Titan arum in person, I highly recommend it. They are out of the ordinary and demonstrate how diverse plants can be.
If you have the chance to see a Titan arum in person, I highly recommend it. They are out of the ordinary and demonstrate how diverse plants can be.
All of the photos used in this post were taken by Ian Street at the Dartmouth Greenhouse 2016/09.
References & further reading:
Barthlott ,W., Szarzynski, J., Vlek, P., Lobin, W., Korotkova, N. (2008). A torch in the rain forest: thermogenesis of the Titan arum (Amorphophallus titanum). Plant Bio 11:499-505 doi.
Korotkova, N., Barthlott, W. 2009. On the thermogenesis of the Titan arum (Amorphophallus titanum). Plant Sig. Behav. 4:1096-1098 doi.
Johnson, S.D. 2016. Carrion flowers. Curr Biol. 26: R556-R558 doi.
Kew Science Amorphus titanum Discover Kew Fungi and plants page. Accessed 2016/09/30
Wide Screen Arkive Titan Arum photo gallery and info page. Accessed 2016/09/30.
03/01/2017 This post has been updated to clarify some ideas presented.
The Quiet Branches 
Admirable as A. titanum undoubtedly is, readers might enjoy knowing that the Titan arum has smaller relatives that aren’t so hard to find, even in not-so-wild environs, and when caught in bloom offer a bit of the same starting sense of having encountered an alien life form, albeit on a much less awe-inspiring scale.
These are the skunk cabbages — Symplocarpus foetidus is native to the east coast of North
America and Lysichiton americanus to the west. I believe one or both may have been imported as tantalizing exotica by gardeners in the UK, from Victorian times onward. Here in New England, S. foetidus rears its head from boggy, out-of-the-way places in earliest spring, when its amazing heat-producing abilities protect its weird blossoms from frosts that would devastate more familiar specimens. As the season progresses, large hosta-like leaves appear, and the plant becomes an ordinary (though rather large-scale) clump of greenery, easily overlooked. Wherever you live, there are interesting plants about.
LikeLiked by 1 person
Yes, indeed. Skunk cabbage is definitely accessible to those in N. America. And there are more common arums throughout the world too, I believe. Skunk cabbage is fascinating because it heats up in part to melt the last of the winter snow and be the first bloom in the spring, or among the first. Definitely a plant to keep an eye out for. And as you say, wherever you are, there are interesting plants around.
LikeLike