Giant Salvinia

Salvinia molesta

Keys to Identification

  • Giant salvinia is an aquatic fern that floats on the surface of the water in ponds, lakes, and slow moving creeks. It reproduces by spores.
  • It is not known to occur in Colorado at this time but it has been spotted in the past. It is thought that this plant was an accidental introduction to the US through the aquarium trade. It is important to not spread it so cleaning boats and other equipment is an important method of prevention.

Family

True Ferns (Salviniaceae)

Other Names

Kariba weed, African pyle, aquarium watermoss, koi kandy

USDA Code

SAMO5

Legal Status

Colorado Noxious Weed List A

Identification

Lifecycle

Perennial or annual

Growth form

Floating fern, herbaceous forb.

Flower

N/A

Seeds/Fruit

Spores produced in long chains of sporocarps found on the submerged leaves.

Leaves

Upper leaves green with white bristly hairs that are split and resemble eggbeaters. Submerged leaf brown, finely divided.

Stems

Horizontal stems float just below the water’s surface.

Roots

Rootless

Seedling

N/A

Similar Species

Exotics

Salvinia auriculata, S. biloba, S. herzogii

Natives

None

Impacts

Agricultural

Clogs lakes, ponds, streams, irrigation ditches.

Ecological

Forms a dense mat that shades the water. Changes the oxygen content of the water both by preventing surface exchange and decomposing material which accumulates on the bottom surface of the waterbody.

Habitat and Distribution

General requirements

Freshwater lakes, ponds, slow moving streams and rivers. Biomass can double in 7-10 days.

Distribution

Not presently known to occur in Colorado. Found in southern US states.

Historical

Native to South America.

Biology/Ecology

Life cycle

Perennial or annual

Mode of reproduction

Vegetative fragmentation and spores.

Dispersal

Water movement, animals, man, and equipment.

References

Jacono, C.C. The Biology of Salvinia sp., Internet: 7/29/04, Available:http://www.ceris.purdue.edu/napis/pests/gs/facts/bio.html

Jacono, C.C., USGS, Internet: 2/25/03 Available: http://salvinia.er.usgs.gov/html/identification.html

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