Hydrilla
Hydrilla verticillata
Hydrilla has whorls of tiny toothed leaves along long, freely branching stems.
Hydrilla is a bay grass with whorls of tiny, toothed leaves along long, freely branching stems. It grows in freshwater portions of the Chesapeake Bay and most of its tributaries.
Appearance:
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Long, freely branching stems
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Tiny, straight or lance-shaped leaves that usually have visible teeth along the edges
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Leaves grow in whorls of 4-5 along each stem
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Tiny, white flowers in late summer
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Rhizomes grow along or just below bottom sediments
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Roots and small, fleshy tubers grow from the rhizomes
Habitat:
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Grows in fresh waters, but has also been found in brackish waters
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Does not need as much light as other bay grasses, so it can grow in more turbid areas
Range:
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Common in the upper Chesapeake Bay and in most freshwater tributaries
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Native to Africa, Australia and parts of Asia
Predators:
Reproduction and Life Cycle:
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Asexual reproduction takes place when plant fragments, tubers, roots and turions develop into new plants
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Sexual reproduction occurs in late summer, when pollen from male flowers fertilizes female flowers. The seeds that form have about a 50 percent chance of growing into new plants.
Other Facts:
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Introduced to the U.S. in the 1960s through the aquarium trade
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First detected in the Potomac River near Washington, D.C., in 1982. By 1992, it covered 3,000 acres of the river.
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Considered by some to be a nuisance because it can block boating channels and limit water sports
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Has become an excellent habitat for fishes, particularly largemouth bass
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Can be confused with common waterweed. You can distinguish hydrilla by its whorls of 4-5 leaves, the visible teeth along the edges of the leaves, and its fleshy tubers.
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