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Common Name: WaterwheelSpecies: Aldrovanda vesiculosa
Genus: Aldrovanda - Family: Droseraceae


Identifying Traits & General Plant Information

The waterwheel is part of the trapping family of carnivorous plants. It is a rootless aquatic plant, and also the most widely distributed carnivorous plant. Similar to Venus flytraps, in terms of their trapping mechanisms, the waterwheel uses its traps to capture small aquatic invertebrates. In addition to all kinds of aquatic creatures, they are also known to catch mosquito larvae by the head. Interestingly enough, this plant is one of the only capable of rapid movement. The waterwheel prefers to live in clean, shallow warm water ("Aldrovanda vesiculosa," "The Carnivorous Plant FAQ").

Of the approximately nineteen species that once existed, the waterwheel is the only remaining living species of its genus. The waterwheel has fairly limited genetic diversity and therefore the species' populations have decreased over the years.

Close-up of the traps on the waterwheel - notice the delicate trigger hairs.
Close-up of the traps on the waterwheel - notice the delicate trigger hairs.

  • Trap- The traps of the waterwheel are arranged around a central, free-floating stem. Each trap consists of two lobes folded together, also known as a snap trap. The inside of the trap is lined with trigger hairs that sense movement, allowing the plant to close on its food.Just like the traps of a Venus flytrap, the trap lobes of Aldrovanda contain trigger hairs.The trap closes in a number of milliseconds, accounting for it's reputation for rapid movement.

  • Flowers - The waterwheel has small white flowers that emerge about the surface of the water. The flowers are only open for a few hours before retreating underwater to partake in seed production. The seeds of the waterwheel grow in such a way as to keep the cotyledons hidden inside as afood supply for the growing plant.

  • Turions - Aldrovanda form "turions" as a frost survival strategy. During the winter, the tip produces highly reduced non-carnivorous leaves on a shortened stem. The result is a bud of protective leaves which breaks off of the mother plant and sinks to the water bottom, where temperatures are stable and warmer.

  • Reproduction - Waterwheel reproduce through vegetative reproduction. Adult plants generally produce offshoot along the existing plant, resulting in new plants as the tips continue to grow and the old ends die off. The waterwheel has a fairly quick growth rate, thus new plants can be produced in a short period of time ("Aldrovanda vesiculosa).


History

The waterwheel was first recorded in India by Leonard Plukenet in 1696. Plukenet originally named the plant Lenticula pulustris Indica. When Giuseppe Monti studied Italian specimens of the waterwheel in 1747, he instead named the plan Aldrovandia vesiculosa, for the respected Italian naturalist Ulisse Aldrovandi (1522-1605).
Evidently, the name for the genus was originally "Aldrovandia", but when it was misspelled in Carl Linnaeus' Species Plantarum (1753), the incorrect spelling became the accepted way, and it still the way it is spelled today ("Aldrovanda vesiculosa").

Ulisse Aldrovandi
Ulisse Aldrovandi
Leonard Plukenet
Leonard Plukenet
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Plant Distribution & Habitat

The waterwheel is found in Europe, Asia, Africa, and Australia. The wide distribution of A. vesiculosa is thought to be related to the migratory patterns of aquatic based birds. The plants stick to the feet of these birds and are transported to the next location, creating a trail of waterwheels along common migratory paths.They are often found free-floating in coastal shallow freshwater lagoons that are rich in organic matter. It is commonly found in Australian lagoons in the Moruya area on the south coast, the Evans Head area on the north coast ("Water Wheel Plant Profile").

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Threats to the Species

In the regions in Australia (specifically the New South Wales region) where the Waterwheel plants lives, the species has been classified as endangered, and faces a number of threats such as:
  • Destruction of wetland habitats.
  • Pollution and increased turbitity of lagoons.
  • Illegal collection by enthusiasts of carnivorous plants.
  • Competition from aquatic weeds such as Salvinia (Salvinia molesta).
  • Damage caused by spraying aquatic weeds with herbicides.
  • Lack of knowledge of the species distribution and threats.

("Water Wheel Plant Profile")


Interactions with Humans

In general, because the waterwheel is an aquatic plant, it does not generally interact with humans. Humans have done considerable damage to the waterwheel's natural habitat, as is the case with many water-based species of flora and fauna. As humans, and industries, pollute water sources, the habitat of the waterwheel has grown increasingly threatened. Because the waterwheel is not grown as a crop or propagated for private use very often, very few specimens survive. For those involved in the trade and collection of carnivorous plants (yes - that's a real thing), the waterwheel is an extremely rare and desirable acquisition. For the most part, only those high up in the world of carnivorous plant studies can acquire a waterwheel plant.



Watch Swiss carnivorous plant expert Ruedi Furst guide us through the waterwheel's natural habitat.




WILD CARD

So you want to learn how to grow your very own waterwheel? Here are some tips.

California Carnivores ("The largest carnivorous plant shop in the United States") suggests starting with a large plastic tub.
Then put 3" of 1 part peat moss to 1 part clay in the bottom of the tub. Add an inch of sand or aquarium gravel to hold everything down. Plant aquatic monocots like rushes in the bottom to release carbon dioxide, need by the waterwheel. Continue by adding mosquito larvae or water daphnea for a steady supply of prey. Waterwheels require a lot of sun,and be careful of algae that may crowd out the plant.

The Carnivorous Plant Nursery notes that Aldrovanda is a very challenging plant to grow. Use a large tub or tank, 30 gallons or more, but ideally try for an outdoor bog pool. Add 1” of peat moss and leaf litter to the water. Let the pool sit for a week or more before placing the Aldrovanda. Include other submergent, aquatic plants in such as cattail, pickerel weed, water lilies or arrowhead plant.These plants will keep algae growth to a minimum. Aldrovanda requires warm, bright, sunny conditions.

Quick tips to remember:
  • Aldrovanda does not compete well with algae.
  • "Flowering requires prolonged, warmer temperatures around 90°F."
  • Consider growing Aldrovanda outdoors, as they can tolerate frost or a light freeze.


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("Carnivorous Plant Growing Tips," "Waterwheel Plant")

By Kayla Fernandes

Works Cited

"Aldrovanda in Switzerland." Youtube video. http://www.youtube.com/watch?v=6H-0UkhVwtk

"Aldrovanda vesiculosa." Wikipedia. <http://en.wikipedia.org/wiki/Aldrovanda_vesiculosa>.

"The Carnivorous Plant FAQ." The International Carnivorous Plant Society. <http://www.sarracenia.com/faq/faq5040.html>.

"Carnivorous Plant Growing Tips - Aldrovanda vesiculosa." Carnivorous Plant Nursery. <http://www.carnivorousplantnursery.com/info/growingaldrovanda.htm>.

"Waterwheel Plant." California Carnivores. <http://www.californiacarnivores.com/waterwheelplant.aspx>.

"Water Wheel Plant Profile." North South Wales Government Environment & Heritage. < http://www.environment.nsw.gov.au/threatenedSpeciesApp/profile.aspx?id=10035>.