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 genusUtricularia. 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.
Utricularia 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 filiformstolons are the main vegetative "stem" of the plant and can be up to one meter long or longer but are only 1–2mm thick. The stolons are glabrous with 1–5cm 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 2–18cm long, originating from the stolon base into two primary and unequal segments, which are further divided extensively into additional segments. The stalked, ovoid traps, 1–3mm long, are produced on the latter leaf segments and are very numerous.[2]
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 inflorescences, often called a "float". U. inflata typically produces 6 to 8 spokes on the float (sometimes anywhere from 5 to 10), with each spoke 3–10cm long and up to 8mm wide. The apical half of the spokes bear numerous, dichotomously branched leaf-like segments that can also possess some traps. The 20–50cm 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, 3–5mm long. The entire corolla can be 2-2.5cm long and is bright yellow with brown-colored veins on the spur and brown markings on the lower corolla lobe.[2]
This species has a diploidchromosome number of 2n=18 for the most common form and 2n=36 for the larger tetraploid populations.[4] 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.[2]
U. inflata inhabits aquatic environments such as lakes, ditches, and swamps from shallow to deep waters at low altitudes.[2]
Invasiveness
As early as 1980, specimens of U. inflata were beginning to be collected or recorded outside its traditionally accepted range.[5] Populations have been established in Washington state,[5]New York,[6] and Massachusetts.[7] The colonies in Washington are obvious introductions,[8] 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.[6][7] In 2021 a well established and extensive infestation was discovered in Lake Arrowhead in Maine and reported to the Maine Department of Environmental Protection.[9]
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 propagules by waterfowl or herons from U. inflata's native range may be just as likely.[7]
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.[10] 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 macrophyteisoetid 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.[6]
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.[5][8][11] Information on this species in Washington State provided by the state's Department of Ecology includes a statement that U. inflata's presence in Horseshoe Lake was "probably the result of a discarded aquarium."[5] 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.[8] 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.[3][12]
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.[13]U. inflata's 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.[2][6][8][14]
U. inflata has also been reported on lakes such as Pine River Pond in East Wakefield, New Hampshire. [15]
Cultivation
U. inflata in the field
Utricularia 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.[16] 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.[17]
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.[8][18][19]
Utricularia 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.[20] 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.[2]
Utricularia, commonly and collectively called the bladderworts, is a genus of carnivorous plants consisting of approximately 233 species. They occur in fresh water and wet soil as terrestrial or aquatic species across every continent except Antarctica. Utricularia are cultivated for their flowers, which are often compared with those of snapdragons and orchids, especially amongst carnivorous plant enthusiasts.
Genlisea is a genus of carnivorous plants also known as corkscrew plants. The 30 or so species grow in wet terrestrial to semi-aquatic environments distributed throughout Africa and Central and South America. The plants use highly modified underground leaves to attract, trap and digest minute microfauna, particularly protozoans. Although suggested a century earlier by Charles Darwin, carnivory in the genus was not proven until 1998.
Aldrovanda vesiculosa, commonly known as the waterwheel plant, is the sole extant species in the flowering plant genus Aldrovanda of the family Droseraceae. The plant captures small aquatic invertebrates using traps similar to those of the Venus flytrap. 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.
Genlisea margaretae is a carnivorous species in the genus Genlisea native to areas of Madagascar, Tanzania, and Zambia. It has pale bundles of root-like organs up to about 20 cm long under ground that attract, trap, and digest protozoans. These organs are subterranean leaves, which lack chlorophyll. It had been known to possess the smallest known genome of any flowering plant as of 2006, but was later surpassed by the related species Genlisea tuberosa.
Utricularia gibba, commonly known as the humped bladderwort or floating bladderwort, is a small, mat-forming species of carnivorous aquatic bladderwort. It is found on all continents except Antarctica.
Utricularia paulineae is an affixed aquatic carnivorous plant that belongs to the genus Utricularia. It is endemic to the coastal regions of Western Australia.
Utricularia volubilis, the twining bladderwort, is a perennial, affixed aquatic carnivorous plant that belongs to the genus Utricularia. It is endemic to the southwestern coastal region of Western Australia.
Utricularia biloba, the moth bladderwort, is a perennial, terrestrial or aquatic carnivorous plant that belongs to the genus Utricularia. It is endemic to Australia with a distribution along the coastal regions of New South Wales and Queensland.
Utricularia resupinata, popularly known as lavender bladderwort or northeastern bladderwort, is a small perennial subaquatic carnivorous plant that belongs to the genus Utricularia. It is native to eastern Canada, the United States, and Central America. This plant species has an interesting etymology, growth pattern, ecology, and research history. As a plant that is threatened or endangered in many of the States where it is found, it is a candidate for sound conservation efforts.
Utricularia aurea, the golden bladderwort, is a medium- to large-sized suspended aquatic carnivorous plant that belongs to the genus Utricularia. It is the most common and widespread suspended aquatic species in Asia. Its native distribution ranges from India to Japan and Australia.
Utricularia floridana, the Florida yellow bladderwort, is a large affixed aquatic carnivorous plant in the bladderwort genus within the bladderwort family). It is a perennial plant that is endemic to southeastern United States.
Utricularia foliosa, the leafy bladderwort, is a large suspended aquatic carnivorous plant that belongs to the genus Utricularia. It is probably a perennial plant that cultivates in lake, swamps and ponds. U. foliosa is native to Africa and North and South America, widely distributed among many countries. Although, they are widely distributed around the world, very little studies have been contributed to U. foliosa. They like to sprout all year long, and found in large body of water. The environment that Utricularia foliosa are found in are experiencing negative anthropogenic impacts such as drainage and conversion to urban or agricultural activities are causing rapid environmental degradation.
Utricularia macrorhiza, the common bladderwort, is a perennial suspended aquatic carnivorous plant that belongs to the genus Utricularia. U. macrorhiza is native to North America and eastern temperate Asia.
Utricularia minor, the lesser bladderwort, is a small species of perennial carnivorous plant in the family Lentibulariaceae. It is usually found affixed to the substrate but it can also survive suspended in a body of water. U. minor is a circumboreal species and is found in North America, Asia, and Europe.
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.
Utricularia stygia, the arctic bladderwort or Northern bladderwort, is an affixed aquatic carnivorous plant that belongs to the genus Utricularia. U. stygia is native to northern Europe and North America. This species was originally published by Göran Thor in 1987 but the description was not in Latin and was therefore nomenclaturally invalid. Thor validly published the species a year later. The cited difference that separates U. stygia from U. ochroleuca is the shape of the tiny quadrifid glands inside the bladders, specifically at which angle the "arms" of these glands diverge from one another. Thor, when working on the Utricularia of Sweden noted that this distinction alone allowed for consistent species identification. Both Barry Rice and Peter Taylor have expressed concerns regarding how this method applies to other populations around the world.
Utricularia geoffrayi is a small, probably perennial, terrestrial carnivorous plant that belongs to the genus Utricularia. U. geoffrayi is native to Indochina and can be found in Cambodia, Thailand, and Vietnam. It was originally published and described by François Pellegrin in 1920. It grows as a terrestrial plant among short grasses in or around rice fields at altitudes from sea level to 1,300 m (4,265 ft). It has been collected in flower between September and December.
Utricularia heterosepala is a small carnivorous plant that belongs to the genus Utricularia.
The Genus Utricularia: A Taxonomic Monograph is a monograph by Peter Taylor on the carnivorous plant genus Utricularia, the bladderworts. It was published in 1989 by Her Majesty's Stationery Office (HMSO) as the fourteenth entry in the Kew Bulletin Additional Series. It was reprinted for The Royal Botanic Gardens, Kew in 1994.
References
↑ illustration from Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. Vol. 3: 230
1 2 3 United States Department of Agriculture, Natural Resources Conservation Service. 2007. Utricularia inflata. The PLANTS Database. Accessed online: 23 December 2007.
↑ Lewis, W.H., Stripling, H.L., and Ross, R.G. (1962). Chromosome numbers for some angiosperms of the southern United States and Mexico. Rhodora, 64: 147-161.
1 2 3 4 Urban, R.A., Titus, J.E., and Zhu, W.-X. (2006). An invasive macrophyte alters sediment chemistry due to suppression of a native isoetid. Oecologia, 148: 455-463.
1 2 3 Sorrie, Bruce A. (1992). Utricularia inflata Walter (Lentibulariaceae) in Massachusetts. Rhodora, 94(880): 391-392.
↑ First hand information and identification confirmed by Maine DEP and others.
↑ Mitchell, R.S., Maenza-Gmelch, T.E., and Barbour, J.G. (1994). Utricularia inflata Walt. (Lentibulariaceae), new to New York State. Bulletin of the Torrey Botanical Club, 121(3): 295-297.
↑ Washington State Department of Ecology. Swollen Bladderwort. Aquatic Plant Monitoring. Accessed online: 23 December 2007.
↑ Barthlott, W., Porembski, S., Seine, R., and Theisen, I. (2007). The Curious World of Carnivorous Plants: A Comprehensive Guide to Their Biology and Cultivation. Portland, Oregon: Timber Press.
↑ Reinert, G.W. and Godfrey, R.K. (1962). Reappraisal of Utricularia inflata and U. radiata (Lentibulariaceae). American Journal of Botany, 49(3): 213-220.
Utricularia inflataArchived 2008-01-07 at the Wayback Machine at the Michigan State University's Natural Features Inventory website, which includes information on the one collection of U. inflata in Michigan.
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