Utricularia inflata
Encyclopedia
Utricularia inflata, commonly known as the swollen bladderwort, inflated bladderwort, or large floating bladderwort, is a large suspended aquatic carnivorous plant
that belongs to the genus
Utricularia. It is a perennial
that is native to the southeastern coastal plains of the United States
. It has often been confused with U. radiata
, which is similar but smaller than U. inflata. Since 1980, U. inflata has been reported to exist in locations beyond its traditional range, such as the Adirondack Mountains
in New York
, southeastern Massachusetts
, and in Washington State. Studies on the populations in the Adirondacks suggest that an introduction of U. inflata to a location where it naturalizes
can lead to altered sediment chemistry by reducing the net primary productivity of native species. It is also listed by the state of Washington as a problematic species because of the dense mat-forming habit of this aquatic Utricularia. It is one of the few carnivorous plants that can be invasive
.
s are the main vegetative "stem" of the plant and can be up to one meter long or longer but are only 1–2 mm thick. The stolons are glabrous with 1–5 cm between branched divisions. Occasionally the stolons will produce floating air shoots at the water's surface and tuber
-like organs in the substrate
. Its filiform leaf-like structures appear to be additional branches off the main stolon and are tiny, filament-like structures that are not true leaves, though the terminology is often disputed among experts. The leaf structures are numerous and anywhere from 2–18 cm long, originating from the stolon base into two primary and unequal segments, which are further divided extensively into additional segments. The stalked, ovoid traps, 1–3 mm long, are produced on the latter leaf segments and are very numerous.
In its native range, U. inflata, a perennial species, can begin to flower in January and may continue through June. In this phase of its growth it produces the most visible and noticeable morphological
features of the species: a floating spoke-like whorl
of spongy structures at the water's surface that support the inflorescence
s, often called a "float". U. inflata typically produces 6 to 8 spokes on the float (sometimes anywhere from 5 to 10), with each spoke 3–10 cm long and up to 8 mm wide. The apical half of the spokes bear numerous, dichotomously branched leaf-like segments that can also possess some traps. The 20–50 cm long erect inflorescences are produced from the center of the floating whorl and are usually solitary or possess very few scapes
for each whorl. An individual plant can produce several whorls and inflorescences, but they are typically distant from each other. The inflorescences produce 9-14 (sometimes 4-17) flowers with unequal calyx lobes, 3–5 mm long. The entire corolla can be 2-2.5 cm long and is bright yellow with brown-colored veins on the spur
and brown markings on the lower corolla lobe.
This species has a diploid chromosome
number of 2n = 18 for the most common form and 2n = 36 for the larger tetraploid
populations. The larger tetraploid "race
", as Peter Taylor
called it, can be up to twice as large as the regular diploid species. Populations of this race have been located in Florida.
U. inflata is native to the southeastern United States
. Peter Taylor's 1989 taxonomic monograph
listed the following states where native populations of this species have been located: Alabama
, Arkansas
, Delaware
, Florida
, Georgia
, Kentucky
, Louisiana
, New Jersey
, North
and South Carolina
, Tennessee
, Texas
, and Virginia
. In addition to these states, the United States Department of Agriculture
's online PLANTS database acknowledges populations in Connecticut
, Maryland
, Michigan
, Mississippi
, New York
, Oklahoma
, and Pennsylvania
. The states of Maryland, Michigan, and New York have classified U. inflata as an endangered
or threatened species
while Tennessee has listed it as a species with "special concern".
U. inflata inhabits aquatic environments such as lakes, ditches, and swamps from shallow to deep waters at low altitudes.
, and Massachusetts
. The colonies in Washington are obvious introductions
, but while the populations in New York and Massachusetts are most likely the result of recent introductions, it is more difficult to say with certainty how they were introduced.
In southeastern Massachusetts, several samples of U. inflata have been gathered from Federal Pond
beginning in 1990, representing its first collection north of New Jersey on the east coast. Bruce Sorrie has identified a substantial population in this location. Sorrie indicated that human-aided introduction of this species to Massachusetts is likely since Federal Pond has been used for various purposes since the late 18th century, though Sorrie also notes that transfer of propagule
s by waterfowl
or heron
s from U. inflatas native range may be just as likely.
Three years after the first collection in Massachusetts, a study of the area around Spruce Pond in Orange County
, New York yielded the first record for U. inflata in New York State. The authors of the study speculate that, unlike the population found in Massachusetts, it is unlikely that the population in Spruce Pond was the result of human introduction because the pond is in a remote area and rarely used. More recently in 2005, a study in northern New York identified populations of U. inflata in six lakes in the Adirondack Mountains
, representing another northern extension of its range. In two of these lakes U. inflata was the most frequently encountered species in 2000, whereas a census of the lakes found no U. inflata whatsoever in 1983. This impressive growth in what is probably a new location for the species is similar to the growth patterns of other invasive
aquatic plant species. The authors of this study also noted that at one of these sites, many of the native species declined in frequency or could not be found, possibly due to the presence and proliferation of U. inflata. Lab experiments and observations in the field supported the authors' hypothesis that the presence of U. inflata in Adirondack lake systems damages the natural nutrient cycles that sustain the native flora. U. inflata likely shades out the native flora, specifically Eriocaulon aquaticum, a submersed macrophyte
isoetid that releases oxygen into the sediment. In this case, U. inflata could indirectly change the biogeochemical cycle
in the Adirondack lakes by hindering the growth of native isoetid macrophytes and subsequently having a negative effect on the proper balance of sediment chemistry. The consequence of this may include enhanced growth of algae
and other changes to the ecology of the freshwater ecosystems that it may invade.
Even earlier than the collections in Massachusetts and New York, a population of U. inflata was located in Horseshoe Lake in Kitsap County
, Washington in 1980. Since then, further specimens of U. inflata have been recorded from other Puget Sound
area lakes in Kitsap, Mason, Pierce
, and Thurston counties. One population has even been recorded from the more southern Silver Lake
in Cowlitz County
. Information on this species in Washington State provided by the state's Department of Ecology
includes a statement that U. inflatas presence in Horseshoe Lake was "probably the result of a discarded aquarium." Washington's Department of Ecology also indicates that in the areas where it occurs, U. inflata forms dense floating mats, becoming a nuisance for recreational activities. Residents of Lake Limerick, which has extensive populations of U. inflata, spend thousands of dollars each summer to rid their lake of the dense, weedy mats. A variety of control methods have been used to control the weed, including a sonar
treatment, biocontrol utilizing grass carp
, and manual extraction. Washington considers this species to be problematic but has not classified it as a noxious weed. Instead, it is on a monitor list of wetland and aquatic species under quarantine, meaning that it is prohibited to sell this species and it may be included on the state's noxious weed list in the future.
Most carnivorous plant species require very specific environmental conditions to thrive. This narrow habitat tolerance means that many carnivorous plants are threatened or endangered in their native ranges. U. inflatas ability to thrive in a variety of locations that it has been introduced to represents an ability to tolerate a much larger range of habitats than most carnivorous plant species.
U. inflata is one of the many Utricularia species that is cultivated by carnivorous plant enthusiasts. Because it requires no dormancy
and due to its swift growth, it is one of the easier suspended aquatic species to cultivate. Barry Rice, author of Growing Carnivorous Plants, says that this species is the easiest suspended aquatic Utricularia that he has grown. Rice also mentions that U. inflata has been used as an aid in the cultivation of particularly difficult species, such as Aldrovanda vesiculosa, that are much more sensitive to high nutrient concentrations. When growing these species together, U. inflata will grow rapidly in the presence of higher nutrients, which allows A. vesiculosa to enjoy the conditions it thrives in.
Rice, the Washington Department of Ecology, and the United States Geological Survey
's Nonindigenous Aquatic Species information resource all indicate that cultivation of this species is suspected as the most likely source of its introduction into Horseshoe Lake in Washington. The spread from lake to lake in Washington is probably the result of waterfowl moving from lake to lake and carrying plants or propagules with them.
U. inflata was first named and described by Thomas Walter
in 1788. U. radiata has often been mistaken for U. inflata because of their similar morphology and overlapping distribution. In the past, U. radiata has been misidentified as U. inflata or placed at the rank of variety. U. radiata was first identified by Alvan Wentworth Chapman
in 1860 as U. inflata var. minor and noted that it was "in every way smaller" than U. inflata. John Kunkel Small
in 1903 was the first to elevate U. inflata var. minor to the species level under the name U. radiata. Further studies of the two taxa
were mixed on how to treat them. In 1950, Merritt Lyndon Fernald
treated them as two varieties of the same species while Henry Gleason
considered them to be different, but allied species in 1952. In 1962, Grady Reinert and R. K. Godfrey further supported the separation of the two taxa into different species. Peter Taylor's authoritative monograph of the genus in 1989 solidified the distinctiveness of the two species.
Carnivorous plant
Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...
that belongs to the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Utricularia. It is a perennial
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
that is native to the southeastern coastal plains of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. It has often been confused with U. radiata
Utricularia radiata
Utricularia radiata, the little floating bladderwort, is a medium-sized suspended aquatic carnivorous plant that belongs to the genus Utricularia. U. radiata is endemic to North America....
, which is similar but smaller than U. inflata. Since 1980, U. inflata has been reported to exist in locations beyond its traditional range, such as the Adirondack Mountains
Adirondack Mountains
The Adirondack Mountains are a mountain range located in the northeastern part of New York, that runs through Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer, Lewis, Saint Lawrence, Saratoga, Warren, and Washington counties....
in New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
, southeastern Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
, and in Washington State. Studies on the populations in the Adirondacks suggest that an introduction of U. inflata to a location where it naturalizes
Naturalisation (biology)
In biology, naturalisation is any process by which a non-native organism spreads into the wild and its reproduction is sufficient to maintain its population. Such populations are said to be naturalised....
can lead to altered sediment chemistry by reducing the net primary productivity of native species. It is also listed by the state of Washington as a problematic species because of the dense mat-forming habit of this aquatic Utricularia. It is one of the few carnivorous plants that can be invasive
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
.
Description
U. inflata is one of the larger suspended aquatic species in the genus Utricularia. Like all aquatic Utricularia, U. inflata has no true roots or leaves. The filiform stolonStolon
In biology, stolons are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external skeletons.-In botany:...
s are the main vegetative "stem" of the plant and can be up to one meter long or longer but are only 1–2 mm thick. The stolons are glabrous with 1–5 cm between branched divisions. Occasionally the stolons will produce floating air shoots at the water's surface and tuber
Tuber
Tubers are various types of modified plant structures that are enlarged to store nutrients. They are used by plants to survive the winter or dry months and provide energy and nutrients for regrowth during the next growing season and they are a means of asexual reproduction...
-like organs in the substrate
Substrate (marine biology)
Stream substrate is the material that rests at the bottom of a stream. There are several classification guides. One is:*Mud – silt and clay.*Sand – Particles between 0.06 and 2 mm in diameter.*Granule – Between 2 and 4 mm in diameter....
. Its filiform leaf-like structures appear to be additional branches off the main stolon and are tiny, filament-like structures that are not true leaves, though the terminology is often disputed among experts. The leaf structures are numerous and anywhere from 2–18 cm long, originating from the stolon base into two primary and unequal segments, which are further divided extensively into additional segments. The stalked, ovoid traps, 1–3 mm long, are produced on the latter leaf segments and are very numerous.
In its native range, U. inflata, a perennial species, can begin to flower in January and may continue through June. In this phase of its growth it produces the most visible and noticeable morphological
Plant morphology
Plant morphology or phytomorphology is the study of the physical form and external structure of plants. This is usually considered distinct from plant anatomy, which is the study of the internal structure of plants, especially at the microscopic level...
features of the species: a floating spoke-like whorl
Whorl (botany)
In botany, a whorl is an arrangement of sepals, petals, leaves, or branches in which all the parts are attached at the same point and surround or wrap around the stem.There are four whorls in a general flower...
of spongy structures at the water's surface that support the inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
s, often called a "float". U. inflata typically produces 6 to 8 spokes on the float (sometimes anywhere from 5 to 10), with each spoke 3–10 cm long and up to 8 mm wide. The apical half of the spokes bear numerous, dichotomously branched leaf-like segments that can also possess some traps. The 20–50 cm long erect inflorescences are produced from the center of the floating whorl and are usually solitary or possess very few scapes
Scape (botany)
In botany, scapes are leafless flowering stems that rise from the ground. Scapes can have a single flower or many flowers, depending on the species....
for each whorl. An individual plant can produce several whorls and inflorescences, but they are typically distant from each other. The inflorescences produce 9-14 (sometimes 4-17) flowers with unequal calyx lobes, 3–5 mm long. The entire corolla can be 2-2.5 cm long and is bright yellow with brown-colored veins on the spur
Spur (biology)
A spur in botany is a spike, usually part of a flower.In certain plants, part of a sepal or petal develops into an elongated hollow spike extending behind the flower, containing nectar which is sucked by long-tongued animals . Plants with such structures include Delphinium, Aquilegia, Piperia, and...
and brown markings on the lower corolla lobe.
This species has a diploid chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
number of 2n = 18 for the most common form and 2n = 36 for the larger tetraploid
Polyploidy
Polyploid is a term used to describe cells and organisms containing more than two paired sets of chromosomes. Most eukaryotic species are diploid, meaning they have two sets of chromosomes — one set inherited from each parent. However polyploidy is found in some organisms and is especially common...
populations. The larger tetraploid "race
Race (biology)
In biology, races are distinct genetically divergent populations within the same species with relatively small morphological and genetic differences. The populations can be described as ecological races if they arise from adaptation to different local habitats or geographic races when they are...
", as Peter Taylor
Peter Taylor (botanist)
Peter Geoffrey Taylor was a British botanist who worked at Royal Botanic Gardens, Kew throughout his career in botany. Taylor was born in 1926 and joined the staff of the herbarium at Kew in 1948. He published his first new species, Utricularia pentadactyla, in 1954...
called it, can be up to twice as large as the regular diploid species. Populations of this race have been located in Florida.
Distribution and habitat
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Peter Taylor's 1989 taxonomic monograph
Monograph
A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...
listed the following states where native populations of this species have been located: Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
, Arkansas
Arkansas
Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...
, Delaware
Delaware
Delaware is a U.S. state located on the Atlantic Coast in the Mid-Atlantic region of the United States. It is bordered to the south and west by Maryland, and to the north by Pennsylvania...
, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
, Kentucky
Kentucky
The Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...
, Louisiana
Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...
, New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
, North
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
and South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
, Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...
, Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, and Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
. In addition to these states, the United States Department of Agriculture
United States Department of Agriculture
The United States Department of Agriculture is the United States federal executive department responsible for developing and executing U.S. federal government policy on farming, agriculture, and food...
's online PLANTS database acknowledges populations in Connecticut
Connecticut
Connecticut is a state in the New England region of the northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, and the state of New York to the west and the south .Connecticut is named for the Connecticut River, the major U.S. river that approximately...
, Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
, Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....
, Mississippi
Mississippi
Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...
, New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
, Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
, and Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
. The states of Maryland, Michigan, and New York have classified U. inflata as an endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
or threatened species
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
while Tennessee has listed it as a species with "special concern".
U. inflata inhabits aquatic environments such as lakes, ditches, and swamps from shallow to deep waters at low altitudes.
Invasiveness
As early as 1980, specimens of U. inflata were beginning to be collected or recorded outside its traditionally accepted range. Populations have been established in Washington state, New YorkNew York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
, and Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
. The colonies in Washington are obvious introductions
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
, but while the populations in New York and Massachusetts are most likely the result of recent introductions, it is more difficult to say with certainty how they were introduced.
In southeastern Massachusetts, several samples of U. inflata have been gathered from Federal Pond
Federal Pond
Federal Pond is a pond in Carver and Plymouth, Massachusetts. A small portion of the northeastern shore of the pond is in the Myles Standish State Forest. The pond is located southwest of Rocky Pond and Curlew Pond, and northeast of Dunham Pond. Two unnamed islands lie in the middle of the pond...
beginning in 1990, representing its first collection north of New Jersey on the east coast. Bruce Sorrie has identified a substantial population in this location. Sorrie indicated that human-aided introduction of this species to Massachusetts is likely since Federal Pond has been used for various purposes since the late 18th century, though Sorrie also notes that transfer of propagule
Propagule
In horticulture, a propagule is any plant material used for the purpose of plant propagation. In asexual reproduction, a propagule may be a woody, semi-hardwood, or softwood cutting, leaf section, or any number of other plant parts. In sexual reproduction, a propagule is a seed or spore...
s by waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
or heron
Heron
The herons are long-legged freshwater and coastal birds in the family Ardeidae. There are 64 recognised species in this family. Some are called "egrets" or "bitterns" instead of "heron"....
s from U. inflatas native range may be just as likely.
Three years after the first collection in Massachusetts, a study of the area around Spruce Pond in Orange County
Orange County, New York
Orange County is a county located in the U.S. state of New York. It is part of the Poughkeepsie–Newburgh–Middletown, NY Metropolitan Statistical Area and is located at the northern reaches of the New York metropolitan area. The county sits in the state's scenic Mid-Hudson Region of the Hudson Valley...
, New York yielded the first record for U. inflata in New York State. The authors of the study speculate that, unlike the population found in Massachusetts, it is unlikely that the population in Spruce Pond was the result of human introduction because the pond is in a remote area and rarely used. More recently in 2005, a study in northern New York identified populations of U. inflata in six lakes in the Adirondack Mountains
Adirondack Mountains
The Adirondack Mountains are a mountain range located in the northeastern part of New York, that runs through Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer, Lewis, Saint Lawrence, Saratoga, Warren, and Washington counties....
, representing another northern extension of its range. In two of these lakes U. inflata was the most frequently encountered species in 2000, whereas a census of the lakes found no U. inflata whatsoever in 1983. This impressive growth in what is probably a new location for the species is similar to the growth patterns of other invasive
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
aquatic plant species. The authors of this study also noted that at one of these sites, many of the native species declined in frequency or could not be found, possibly due to the presence and proliferation of U. inflata. Lab experiments and observations in the field supported the authors' hypothesis that the presence of U. inflata in Adirondack lake systems damages the natural nutrient cycles that sustain the native flora. U. inflata likely shades out the native flora, specifically Eriocaulon aquaticum, a submersed macrophyte
Macrophyte
A macrophyte is an aquatic plant that grows in or near water and is either emergent, submergent, or floating. In lakes macrophytes provide cover for fish and substrate for aquatic invertebrates, produce oxygen, and act as food for some fish and wildlife....
isoetid that releases oxygen into the sediment. In this case, U. inflata could indirectly change the biogeochemical cycle
Biogeochemical cycle
In ecology and Earth science, a biogeochemical cycle or substance turnover or cycling of substances is a pathway by which a chemical element or molecule moves through both biotic and abiotic compartments of Earth. A cycle is a series of change which comes back to the starting point and which can...
in the Adirondack lakes by hindering the growth of native isoetid macrophytes and subsequently having a negative effect on the proper balance of sediment chemistry. The consequence of this may include enhanced growth of algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
and other changes to the ecology of the freshwater ecosystems that it may invade.
Even earlier than the collections in Massachusetts and New York, a population of U. inflata was located in Horseshoe Lake in Kitsap County
Kitsap County, Washington
Kitsap County is a county located in the U.S. state of Washington, named after Chief Kitsap of the Suquamish tribe. As of 2011 state estimate, its population was 253,900. Its county seat is at Port Orchard, and its largest city is Bremerton....
, Washington in 1980. Since then, further specimens of U. inflata have been recorded from other Puget Sound
Puget Sound
Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...
area lakes in Kitsap, Mason, Pierce
Pierce County, Washington
right|thumb|[[Tacoma, Washington|Tacoma]] - Seat of Pierce CountyPierce County is the second most populous county in the U.S. state of Washington. Formed out of Thurston County on December 22, 1852, by the legislature of Oregon Territory...
, and Thurston counties. One population has even been recorded from the more southern Silver Lake
Silver Lake (Washington)
Silver Lake, in Washington, United States, is both a marsh and unincorporated area located about west of Mount St. Helens. It is home to a nature trail, and the visitor center for the Mount St. Helens National Monument. The lake itself is in size and camping is available at Seaquest State Park,...
in Cowlitz County
Cowlitz County, Washington
Cowlitz County is a county located in the U.S. state of Washington. As of the 2010 census its population was 102,410. It forms the Longview, Washington, Metropolitan Statistical Area which encompasses all of Cowlitz County. The county seat is at Kelso, and its largest city is Longview...
. Information on this species in Washington State provided by the state's Department of Ecology
Washington Department of Ecology
The Washington Department of Ecology, or simply, Ecology, is an environmental regulatory agency for the State of Washington. The department administers laws and regulations pertaining to the areas of water quality, water rights and water resources, shoreline management, toxics clean-up, nuclear...
includes a statement that U. inflatas presence in Horseshoe Lake was "probably the result of a discarded aquarium." Washington's Department of Ecology also indicates that in the areas where it occurs, U. inflata forms dense floating mats, becoming a nuisance for recreational activities. Residents of Lake Limerick, which has extensive populations of U. inflata, spend thousands of dollars each summer to rid their lake of the dense, weedy mats. A variety of control methods have been used to control the weed, including a sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
treatment, biocontrol utilizing grass carp
Grass carp
The grass carp is a herbivorous, freshwater fish species of family Cyprinidae, and the only species of the genus Ctenopharyngodon. It is cultivated in China for food, but was introduced in Europe and the United States for aquatic weed control...
, and manual extraction. Washington considers this species to be problematic but has not classified it as a noxious weed. Instead, it is on a monitor list of wetland and aquatic species under quarantine, meaning that it is prohibited to sell this species and it may be included on the state's noxious weed list in the future.
Most carnivorous plant species require very specific environmental conditions to thrive. This narrow habitat tolerance means that many carnivorous plants are threatened or endangered in their native ranges. U. inflatas ability to thrive in a variety of locations that it has been introduced to represents an ability to tolerate a much larger range of habitats than most carnivorous plant species.
Cultivation
Dormancy
Dormancy is a period in an organism's life cycle when growth, development, and physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be closely associated with environmental conditions...
and due to its swift growth, it is one of the easier suspended aquatic species to cultivate. Barry Rice, author of Growing Carnivorous Plants, says that this species is the easiest suspended aquatic Utricularia that he has grown. Rice also mentions that U. inflata has been used as an aid in the cultivation of particularly difficult species, such as Aldrovanda vesiculosa, that are much more sensitive to high nutrient concentrations. When growing these species together, U. inflata will grow rapidly in the presence of higher nutrients, which allows A. vesiculosa to enjoy the conditions it thrives in.
Rice, the Washington Department of Ecology, and the United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
's Nonindigenous Aquatic Species information resource all indicate that cultivation of this species is suspected as the most likely source of its introduction into Horseshoe Lake in Washington. The spread from lake to lake in Washington is probably the result of waterfowl moving from lake to lake and carrying plants or propagules with them.
Botanical history
Thomas Walter (botanist)
Thomas Walter was a British-born American botanist. He is best known for his book Flora Caroliniana , an early yet fairly complete catalog of the flowering plants of South Carolina.-References:...
in 1788. U. radiata has often been mistaken for U. inflata because of their similar morphology and overlapping distribution. In the past, U. radiata has been misidentified as U. inflata or placed at the rank of variety. U. radiata was first identified by Alvan Wentworth Chapman
Alvan Wentworth Chapman
Alvan Wentworth Chapman was an American physician and botanist who wrote Flora of the Southern United States, the first comprehensive description of US plants in any region beyond the northeastern states.-Education:...
in 1860 as U. inflata var. minor and noted that it was "in every way smaller" than U. inflata. John Kunkel Small
John Kunkel Small
John Kunkel Small was an American botanist.He was the first Curator of Museums at The New York Botanical Garden, a post in which he served from 1898 until 1906. From 1906 to 1934 he was Head Curator and then from 1934 until his death he was Chief Research Associate and Curator...
in 1903 was the first to elevate U. inflata var. minor to the species level under the name U. radiata. Further studies of the two taxa
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
were mixed on how to treat them. In 1950, Merritt Lyndon Fernald
Merritt Lyndon Fernald
Merritt Lyndon Fernald was an American botanist. In his time he was regarded as the most respected scholar of the taxonomy and phytogeography of the vascular plant flora of temperate eastern North America. He published more than 850 scientific papers and wrote and edited the seventh and eighth...
treated them as two varieties of the same species while Henry Gleason
Henry Gleason
Henry Allan Gleason was a noted American ecologist, botanist, and taxonomist, most recognized for his endorsement of the individualistic/open community concept of ecological succession.- Life and work :...
considered them to be different, but allied species in 1952. In 1962, Grady Reinert and R. K. Godfrey further supported the separation of the two taxa into different species. Peter Taylor's authoritative monograph of the genus in 1989 solidified the distinctiveness of the two species.
External links
- Utricularia inflata at the Michigan State University's Natural Features Inventory website, which includes information on the one collection of U. inflata in Michigan.