Family:
Hydrocharitaceae
(Tape grass family)
Other Names:
waterthyme,
Florida elodea
USDA Code:
HYVE3
Legal Status:
Colorado
Noxious Weed List A
New in Colorado – call your county weed
supervisor if you find this plant!
IDENTIFICATION
Lifecycle:
Perennial
aquatic
Growth form:
forb/herb
Flower:
Female
flowers tiny and white, with 6 petals. Male flowers tiny
greenish, closely attached to the leaf axle
Seeds/Fruit:
Yellowish
turions ("potato-like" tubers). Can remain viable for 4
years.
Leaves:
Leaves
are small, pointed and arraigned in whorls of 4 to 8 along
the stem. Leaf margins are distinctly saw toothed.
Stems:
Submersed
stems are long and slender that branch profusely at the
water surface. Stem fragments are one means of reproduction
Roots:
Roots in
the hydro soil, adventurous roots are white.
Other:
This
plant is noticeable rough when pulled through the hand.
Southern populations (US) overwinter as perennials; northern
populations overwinter and regrow from tubers.
SIMILAR SPECIES:
Exotics:
Egaria Egaria
densa
Natives:
Elodea Elodea
canadensis
IMPACTS
Agricultural:
Could
severely impact the Colorado’s system of water delivery
(irrigation ditches and canals).
Ecological:
Can
grow in natural water bodies displacing native plants.
Other:
In the
South hydrilla impacts the recreational use of water bodies
for boating, fishing and swimming. Major infestations limit
sport fish size and weight.
HABITAT AND DISTRIBUTION
General requirements:
Aquatic
plant. In Russia hydrilla grows as far north as 50° N
Latitude (the equivalent of the USA/Canadian Border)
Distribution:
Arizona,
Atlantic Coast States to Connecticut (Excluding; New Jersey
and New York), California, Gulf Coast States and Tennessee.
No infestations of this plant have been documented in
Colorado.
Historical:
Dioecious
type native to India, monoecious plants native to Korea.
Beleaved to have been brought to Florida in the 1950’s for
use as an aquarium plant.
BIOLOGY/ECOLOGY
Life cycle:
Perennial
Mode of reproduction:
Mainly plant
fragments and turions (vegetative structures)
Seed production:
Minimal
Seed bank:
Unknown
Dispersal:
Water movement,
animals, man, recreation, equipment
REFERENCES
Aquatic,
Wetland and Invasive Plant
Particulars
and Photographs
University
of Florida, Center for Aquatic and Invasive Plants
http://aquat1.ifas.ufl.edu/hyvepic.html
Non-Native
Invasive Aquatic Plants in the United States
Center
for Aquatic and Invasive Plants, University of Florida
and Sea Grant
http://plants.ifas.ufl.edu/seagrant/hydver2.html
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