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World’s Largest Water Lily Discovered … in a Herbarium Drawer at Kew Gardens

Yes, 177 years after the first specimen was dried and brought to Kew Gardens in London, where it remained in a drawer in the herbarium awaiting further study, the mysterious Bolivian giant water lily—the world’s largest water lily—was finally identified … as a species new to science.

Two people inspecting herbarium specimens of giant water lily.
Herbarium specimens of water lilies really don’t appear that impressive to gardeners, but they reveal a lot to botanists like Oscar Pérez Escobar and Natalia Przelomska. Photo: RBG Kew

This is not unusual. Museums and botanical gardens all over the world store tens of thousands of unidentified specimens of both living and fossil animals and plants awaiting study. But there are far more plants and animals to study than scientists able to do the job.

Recognizing a New Species

Carlos Magdalena, senior botanical horticulturist at Kew Gardens, with Victoria boliviana in Kew’s Princess of Wales Conservatory. Photo: RBG Kew

Although closely related to the two other giant water lily species, the Amazonian giant water lily (Victoria amazonica) and the Santa Cruz giant water lily (V. cruziana), this particular plant didn’t look quite right. Or at least that‘s what Carlos Magdalena, a senior botanical horticulturist at Kew Gardens and one of the world’s greatest experts on water lilies, felt. He realized the newly rediscovered plant had considerable differences from the others, not only physically, but, he suspected, genetically. To test his theory, he obtained viable seeds from Bolivia and grew them side by side with the two other species in Kew’s greenhouses.

Comparing leaves of Victoria cruziana (green underneath) and Victoria boliviana (red underneath)
Leaf of Victoria cruziana (left) and Victoria boliviana (right). Credit RBG Kew. (2).jpg

From the very start, it was clear this plant was something different. Neither the seeds nor the leaves nor even the flowers are quite like the others.

He named the species V. boliviana, for it is found only in the Llanos de Moxos floodplains of the Amazonian and Paraná river basins of Bolivia and nowhere else in the world. It is genetically quite distinct from the other two. It turns out the new species is most closely related to V. cruziana, but that the two diverged around a million years ago.

The giant water lily genus was named Victoria in 1852 for the recently crowned Queen Victoria.

Huge!

Two people measuring the leaves of Victoria boliviana.
Lucy Smith and Carlos Magdalena measuring the leaves of Victoria boliviana in Kew’s Princess of Wales Conservatory. Photo: RBG Kew

And it’s a monster of a plant. The floating leaves look like a giant pie plate with a raised rim around the edges. They measure up to 3.2 m (10.5 feet) in diameter, one-third larger than the other species. The trained eye will notice differences in the spines that cover the stems and underside of the leaf, the flower’s form, size and number of petals, even the leaf shape and color.

Six-year old boy sitting on a Victoria boliviana leaf.
Six-year old boy sitting on a Victoria boliviana leaf in Kew’s Princess of Wales Conservatory. Photo: RBG Kew

A leaf is strong enough to hold a person of up to 80 kg (176 lb) sitting on its surface if you can convince said person to sit quietly … but jumping would quickly dump the participant into caiman-infested waters, so is generally frowned upon.

A Monster in More Ways Than One

Victoria boliviana leaf covered with vicious spines.
Victoria boliviana’s leaf, as well as its petiole (partly exposed), are covered in vicious spines. Photo: RBG Kew

A look at the sharp spines up to 2.5 cm (1 inch) long that coat the leaf’s petiole and underside warn you that this plant is not designed for cuddling. It’s actually quite a brute!

The spines almost certainly thwart marauding animals, such as leaf-eating fish and manatees, but that’s not necessarily their main purpose. They actually evolved mostly to be vicious plant killers! The Bolivian giant water lily uses its spines to decimate its competition. It attacks other plants in the lakes, ponds and rivers where it lives. It inevitably takes over the entire body of water by the end of the season so that, from above, all you see are a series of densely packed, monstrously huge, round leaves.

Go With the Flow!

Here’s how the plant accomplishes this.

First, it’s capacity to adapt to its environment is quite astounding. Most of these bodies of water are seasonal. They can vary between less than 1 m (3 feet) deep some years to more than 8 m (26 feet) others. The plant sends out leaves of the appropriate length each year. Imagine, the crown of the plant can be more than 8 m (26 feet) deep under very dark—almost black!—water, colored by tannins coming from nearby vegetation.

Leaf stlll tightly closed with numerous spines.
As a new leaf rises to the surface, it’s clenched tightly closed, revealing its nasty spines. Photo: Lucy Smith, RBG Kew
Spiked fail. Ill.: Deluge, openclipart.org

When a new leaf rises from the crown, it’s fully enrolled into a spike like a clenched fist and covered in spines. It looks a lot like a spiked flail, that medieval weapon with a ball covered in spine on the end of a chain. And is used much like one. When it reaches the surface of the water, it starts to spin clockwise in a larger and larger circle. This occurs because the petiole grows a bit faster on one side than the other, causing it to turn as it expands. As it does, the spines grab, tear, puncture and crush nearby plants, like an aquatic weed whacker.

Once it has cleared a space, the leaf starts to unfurl, expanding outward as it does. In doing so, it catches any remaining plants with its spines. It then covers them, dragging them underneath to drown in the sunless darkness the huge leaf creates.

Is anyone surprised that the underside of the leaf is blood red?

A Bad Neighbor

Carlos Magdalena, Kew’s water lily expert, standing in hip waders near a wild plant of Victoria boliviana.
The water lily uses its spines and huge leaves to eliminate competing plants. Here you can see a specimen with Carlos Magdalena, Kew’s water lily expert. Photo: Cesar David Salazar

This plant doesn’t like to share its space. Each plant produces up to 10 leaves a month and can have 45 leaves all told, eventually covering a surface about the size of the average urban backyard! The sheer density of the leaves means virtually no light can reach into the depths below. Without sunlight, algae can’t grow, so the numerous little creatures that feed on algae almost disappear and a silent, nearly lifeless environment forms.

You could say the Bolivian victoria is the beaver of the plant world: it largely creates its own environment!

Two people examining underside of giant water lily leaf with numerous ribs.
Lucy Smith and Carlos Magdalena examining the air-filled ribs under a leaf of Victoria boliviana: Photo: RBG Kew

The enormous leaves manage to float on the water thanks to surface tension and thick air-filled ribs, clearly seen if you flip the leaf over. They have an intricate and highly geometric shape you would think only a team of engineers could invent.

The leaves, furthermore, turn up at the edges to keep water from washing in. However, when that does happen, as after a rain shower, there are tiny holes, barely visible, designed to let excess water drain out, keeping the top of the leaf clean and dry.

Stunning, Cunning Flowers

It maintains its monstrous habits when it blooms, trapping and holding its insect pollinators hostage.

First night white giant water lily flower.
The nocturnal flowers open white and female the first night, then turn pink or reddish and male the second. Photo: Lucy Smith, RBG Kew

Each flower opens in the evening in the form of a giant white blossom up to 40 cm (16 inches) in diameter with numerous petals. The flower is, at this point, female, with a fertile stigma. At this stage, the flower gives off an intense perfume. It even produces heat, becoming up to 10 ˚C (15 ˚F) warmer than the surrounding air. This is to better diffuse the odor.

The scent and heat attract tiny scarab beetles (Cyclocephala spp.) They arrive in droves to feed on energy-rich staminodes inside the flower … and also to mate. The flower closes during the day, trapping the scarabs inside, but it’s not such a bad prison. After all, they have abundant food from the staminodes, a warm and safe place for them to spend the day and abundant sexual opportunities!

Woman holding giant pink water lily flower that has turned male.
Lucy Smith holds a second-night flower, now pink and male. Photo: RBG Kew

The next evening, the flower opens again, but is now pink to reddish in color and scentless. And it has become male, with fertile stamens that coat the beetles with pollen as they fly away (the second-night flower is of no interest to them, the staminodes they feed on having dried up by then) … to land directly on the intensely perfumed female flower of another plant and repeat the process. This guarantees cross-pollination. 

Adapted to Tough Conditions

Pond in the wild becoming covered with Bolivian water lilies.
Life isn’t easy for Victoria boliviana. Climate change impacts, especially, threaten its fragile existence. Photo: Carlos Carlos Magdalena, RBG Kew

The Bolivian giant water lily (V. boliviana) has a tough life. Its ponds are temporary, drying up completely and pushing it into dormancy after only a few short months of growth. And although seasonal flooding is the norm in the region where it grows, there are years when the rains fail and the dormant rhizome doesn’t survive. But there is a backup plan. This huge plant is perfectly capable of growing as an annual: from seed to bloom in only about 4 months! I suspect it might well be the largest annual ever!

After pollination, the flower stalk starts to contract, pulling the fading blossom underwater. There it remains submerged until the pea-sized seeds mature. Then, surrounded by a buoyant air sac, the seeds float to the surface. Carried away to a new spot, they become embedded in mud as the waterways dry up, ready to germinate when the rains return and fill the ponds again.

How the seeds manage to survive such devastating droughts, though, still remains a mystery. There is much yet to learn about this remarkable plant.


Where to See One?

The Bolivian giant water lily is not actually new to culture. Bolivian botanical gardens, such as the Jardín Botánico Municipal de Santa Cruz de la Sierra and La Rinconada Gardens, grew it, under the mistaken name V. cruziana, for a very long time, possibly the mid-19th century. And still do… with an updated label, of course!

Man with large pink water lily flower and big water lily leaves.
Kew’s horticulturist Alberto Trinco with a male flower of Victoria boliviana in Kew’s Princess of Wales Conservatory. Photo: RBG Kew

And Kew Gardens in London is now showing, as of the summer of 2022, plants of Victoria boliviana in its Water Lily House and in the Princess of Wales Conservatory. In the latter, in fact, you can see all three of the giant water lilies side by side.

And I’m sure many of the gardens already growing giant water lilies will soon adopt this one, too. So, let’s say: “Come see a Bolivian giant water lily: someday soon, in a garden near you!”

5 comments on “World’s Largest Water Lily Discovered … in a Herbarium Drawer at Kew Gardens

  1. Russ Clark

    Don’t suppose I can get a seed of one. And, it probably would not survive in my water garden in Montreal. If it did the raccoons would surely try to eat the flowers as they do with my regular water lilies.

  2. Ferne Dalton

    Wow! it seems like nature has no limit to its ability to adjust…given a whole lot of time.

  3. What a fascinating plant. Interesting that it eradicates all life in the water around it. Seems unusual. Would love to see these beautiful water lilies some day.

  4. Patricia

    Growing your own weed whacker! Amazing. Nature is often weird but always wonderful. This amusing tidbit put a smile on my Sunday morning.

  5. Christine Lemieux

    That is one interesting plant! Amazing!

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