''Aldrovanda vesiculosa'', commonly known as the waterwheel plant, is the sole extant species in the

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

genus ''

Aldrovanda ''Aldrovanda'' is a genus of carnivorous plants encompassing one extant species (''Aldrovanda vesiculosa'', the waterwheel plant) and numerous extinct taxa. The genus is named in honor of the Italian naturalist Ulisse Aldrovandi, the founder of ...

'' of the family

Droseraceae Droseraceae is a family of carnivorous flowering plants, also known as the sundew family. It consists of approximately 180 species in three extant genera. Representatives of the Droseraceae are found on all continents except Antarctica. Descr ...

. The plant captures small aquatic

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s using traps similar to those of the

Venus flytrap The Venus flytrap (''Dionaea muscipula'') is a carnivorous plant native to subtropical wetlands on the East Coast of the United States in North Carolina and South Carolina. It catches its prey—chiefly insects and arachnids—with a trapping ...

. The traps are arranged in whorls around a central, free-floating stem, giving rise to the common name. This is one of the few plant species capable of rapid movement. While the genus ''

'' is now monotypic, up to 19 extinct species are known in the fossil record. While the species displays a degree of morphological plasticity between populations, ''A. vesiculosa'' possesses a very low genetic diversity across its entire range. ''A. vesiculosa'' has declined over the last century to only 50 confirmed extant populations worldwide. These are spread across Europe, Africa, Asia, and Australia. However, potentially invasive populations exist in the

eastern United States The Eastern United States, commonly referred to as the American East, Eastern America, or simply the East, is the region of the United States to the east of the Mississippi River. In some cases the term may refer to a smaller area or the East C ...

. It is kept by hobbyists.

Morphology

''Aldrovanda vesiculosa'' is a rootless aquatic plant. Seedlings develop a short protoroot; however, this fails to develop further and senesces. The plant consists of floating stems reaching a length of . The trap leaves grow in

whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...

of between 5 and 9 in close succession along the plant's central stem. The actual traps are held by petioles which have air sacs that aid in flotation. One end of the stem continually grows while the other end dies off. Growth is quite rapid ( per day in Japanese populations), so that in optimal conditions a new whorl is produced once or more each day.

Trap

The actual traps consist of two lobes which fold together to form a snap-trap similar to that of the

, except that it is smaller and located underwater. These traps, which are twisted so that the trap openings point outward, are lined on the inside by a fine coating of trigger hairs, snapping shut in response to contact with aquatic invertebrates and trapping them. The closing of this trap takes 10–20 milliseconds, making it one of the fastest examples of plant movement in the

kingdom Kingdom commonly refers to: * A monarchy ruled by a king or queen * Kingdom (biology), a category in biological taxonomy Kingdom may also refer to: Arts and media Television * ''Kingdom'' (British TV series), a 2007 British television drama s ...

. This trapping is only possible in warm conditions of at least . Each trap is surrounded by between four and six long

bristle A bristle is a stiff hair or feather (natural or artificial), either on an animal, such as a pig, a plant, or on a tool such as a brush or broom. Synthetic types Synthetic materials such as nylon are also used to make bristles in items such as ...

s that prevent triggering of traps by debris in the water.

Nutrient Acquisition

''A. vesiculosa'' is able to grow in nutrient-poor habitats not only due to its carnivory, but also due to its ability to re-utilize nutrients from senesced shoots, and its high affinity for mineral nutrients in water.

Reproduction

Flowers

The small, solitary white

flowers A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...

of ''A. vesiculosa'' are supported above the water by short peduncles which arise from whorl axes. The flower only opens for a few hours, after which the structure is brought back beneath the water for

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

production. The seeds are cryptocotylar: the

cotyledon A cotyledon (; ; ; , gen. (), ) is a significant part of the embryo within the seed of a plant, and is defined as "the embryonic leaf in seed-bearing plants, one or more of which are the first to appear from a germinating seed." The num ...

s remain hidden within the seed coat and serve as an energy store for the seedling. Flowering, however, is rare in temperate regions and poorly successful in terms of fruit and seed development.

Divisions

''Aldrovanda vesiculosa'' reproduces most often through

vegetative reproduction Vegetative reproduction (also known as vegetative propagation, vegetative multiplication or cloning) is any form of asexual reproduction occurring in plants in which a new plant grows from a fragment or cutting of the parent plant or spec ...

. In favourable conditions, adult plants will produce an offshoot every , resulting in new plants as the tips continue to grow and the old ends die off and separate. Due to the rapid growth rate of this species, countless new plants can be produced in a short period of time in this fashion.

Turions

Winter-hardy ''Aldrovanda'' form turions as a frost survival strategy. At the onset of winter, the growth tip starts producing highly reduced non-carnivorous leaves on a severely shortened stem. This results in a tight bud of protective leaves which, being heavier and having released flotational gases, breaks off the mother plant and sinks to the water bottom, where temperatures are stable and warmer. Here it can withstand temperatures as low as .L. Adamec:
Turion overwintering of aquatic carnivorous plants..
' in: ''Carnivorous plant newsletter.'' Arboretum, Fullerton Ca 28.1999,1, 19–24 In the wild, ''Aldrovanda'' turions have been observed to have a relatively low rate of successful sinking. Those nutritious turions that fail to sink are then grazed by waterfowl or are killed by the onset of frost. In spring when water temperatures rise above , turions reduce their density and float to the top of the water, where they germinate and resume growth. Non-dormant turion-like organs can also form in response to summer drought.

Distribution

''Aldrovanda vesiculosa'' is the second most widely distributed carnivorous plant species, only behind

utricularia ''Utricularia'', commonly and collectively called the bladderworts, is a genus of carnivorous plants consisting of approximately 233 species (precise counts differ based on classification opinions; a 2001 publication lists 215 species).Salmon, Br ...

, native to

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, and Australia. ''Aldrovanda'' is spread mainly through the movement of waterfowl: plants sticking to the feet of a bird are transported to the next aquatic destination on the bird's route. As a result, most ''Aldrovanda'' populations are located along avian migratory routes. Throughout the last century the species has become increasingly rare, listed as extinct in an increasingly large number of countries. In the 1970s, carnivorous plant hobbyists introduced this species to small backyard ponds in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

in the states of

New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

, and the

Catskills The Catskill Mountains, also known as the Catskills, are a physiographic province of the larger Appalachian Mountains, located in southeastern New York. As a cultural and geographic region, the Catskills are generally defined as those areas c ...

of New York, and they may be a potentially invasive species due to their effects on aquatic invertebrates.

Habitat

''A. vesiculosa'' prefers clean, shallow, warm, standing water with bright light, low nutrient levels, and a slightly

acidic In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a ...

pH (around 6). It can be found floating amongst

Juncus ''Juncus'' is a genus of monocotyledonous flowering plants, commonly known as rushes. It is the largest genus in the family Juncaceae, containing around 300 species. Description Rushes of the genus ''Juncus'' are herbaceous plants that superfic ...

, reeds, and even

rice Rice is the seed of the grass species '' Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and '' Porteresia'', both wild and domesticat ...

Botanical history

''Aldrovanda vesiculosa'' was first mentioned in 1696 by

Leonard Plukenet Leonard Plukenet (1641–1706) was an English botanist, Royal Professor of Botany and gardener to Queen Mary. Biography Plukenet published ''Phytographia'' (London, 1691–1696) in four parts in which he described and illustrated rare exotic p ...

, based on collections made in

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...

. He named the plant ''Lenticula pulustris Indica''. The modern botanical name originates from Gaetano Lorenzo Monti, who described Italian specimens in 1747 and named them ''Aldrovandia vesiculosa'' in honor of the Italian naturalist

Ulisse Aldrovandi Ulisse Aldrovandi (11 September 1522 – 4 May 1605) was an Italian naturalist, the moving force behind Bologna's botanical garden, one of the first in Europe. Carl Linnaeus and the comte de Buffon reckoned him the father of natural history st ...

. When

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...

published his '' Species Plantarum'' in 1753, the "i" was dropped from the name (an apparent copying error)Duval-Jouve, 1861, Bull. Soc. Bot. France 8:518-519. to form the modern binomial.

Infraspecific taxa

*''Aldrovanda vesiculosa'' var. ''rubescens'' A.Cross and L.Adamec (2012) *''Aldrovanda vesiculosa'' var. ''aquitanica'' Durieu ''ex'' Diels (1906) ''nom. illeg.'' *''Aldrovanda vesiculosa'' var. ''australis'' Darwin (1876) ''nom. illeg.'' *''Aldrovanda vesiculosa'' var. ''duriaei'' Caspary (1859) ''nom. illeg.'' *''Aldrovanda vesiculosa'' var. ''verticillata'' (Roxb.) Darwin (1876) ''nom. illeg.''

References

External links

''Aldrovanda vesiculosa'' project
{{Authority control Droseraceae Aquatic plants Carnivorous plants of Australia Carnivorous plants of Africa Carnivorous plants of Europe Carnivorous plants of Asia Caryophyllales of Australia Plants described in 1753 Taxa named by Carl Linnaeus