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giant salvinia

Salvinia molesta D. S. Mitchell

USDA PLANTS Symbol: SAMO5
U.S. Nativity: Exotic
Habit: Aquatic


Synonym(s): kariba weed, salvinia, water fern, aquarium watermoss

Appearance
Salvinia molesta is an aquatic fern that floats on the surface of the water. Submerged fronds are “stringy” and resemble roots.
Foliage
Floating leaves are 0.5-1.5 in. (2.5-3.8 cm) long, oblong, and vary in color from green to gold to brown. The surfaces of the leaves have rows of arching hairs that look like little egg-beaters. When young, leaves are smaller and lie flat on the surface of the water.
Flowers
This plant does not produce flowers.
Fruit
S. molesta reproduce by spores and by budding of broken stems or attached nodes.
Ecological Threat
After maturing, S. molesta forms chains of leaves that run together to form thick mats on the surface of the water. These mats restrict oxygen and light availability causing death of the primary producers and disrupting the aquatic food chain. S. molesta is on the Federal Noxious Weed list and can invade most any type of aquatic system. The plant is native to South America and was first introduced into North America as an ornamental.


Identification, Biology, Control and Management Resources

Pest Alert - USDA APHIS PPQ
Biological Control of Invasive Plants in the Eastern United States - USDA Forest Service
Domestic Programs Pest Evaluation - USDA APHIS PPQ
Invasive Plant Atlas of New England - University of Connecticut
Federal Noxious Weed Disseminules of the U.S. - USDA-APHIS
Global Invasive Species Database - Invasive Species Specialist Group
Plant Invaders of Mid-Atlantic Natural Areas - National Park Service and U.S. Fish and Wildlife Service