Synonym(s): Spirodela oligorrhiza, Spirodela punctata
Family: Lemnaceae (Duckweed Family)
Duration and Habit: Perennial Herb
Tiny free-floating aquatic plants comprised of individual fronds that produce fine roots. Mature fronds appear 1.5 to 2 times longer than wide, with widths measuring from 1-3 (or 5) mm. Fronds are narrowly egg-shaped to slightly kidney-shaped and intensely green in color. A waxy layer of cuticle makes plants sparkle in the sunlight. Fronds are not leaves; they may be a reduced form of stem and shoot. The roots number from 2-4 and can range up to 7. All of the roots penetrate the prophyllum (a scale surrounding the base of the frond that covers the point of attachment of the roots)
Ecological Threat: Unknown, but that it has the potential to become a serious nuisance due to its rapid colonization, easy distribution, and quick dispersal rate.
Biology & Spread: Propagation is mainly through vegetative budding of daughter fronds from two pouches at base of the frond. Daughter fronds often remain attached to mother frond by a short stipe so that plants often appear as a cluster of several fronds. This species occasionally reproduces sexually, by seed.
Agriculture: Introducted to nutrient filled waste water ponds as a means to absorb excess nutrients. Also, could potentially be utilized as a fertilizer. Pet/aquarium trade: L. punctata was introducted via the aquarium trade to the USA.
U.S. Habitat: small, quiet, nutrient rich waters such as ponds, ditches, swamps and backwaters; also seasonally intermittent waters.
U.S. Nativity: Native to U.S.
Native Origin: Mo.?? warm and temp. reg. (NatureServe Explorer); Nearly worldwide (HICK).
U.S. Present: AL, AR, AZ, CA, DC, DE, FL, GA, IL, KY, LA, MO, MS, NC, OR, PA, SC, TX, VA
List All Observations of Landoltia punctata reported by Citizen Scientists
Spirodela polyrhiza (giant duckweed)
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Chemical: Diquat is a widely used and effective herbicide because it causes ion leakage in duckweed and other aquatic plants. A Florida study showed that after 20-30 years, Landoltia punctata developed resistance to Diquat and Paraquat herbicides. The mechanism of resistance to Diquat is independent of electron transport in photosynthesis, and therefore is not exclusive to photosynthesis. A separate study indicated that Landoltia punctata was not adequately controlled by Carfentrazone-ethyl at the maximum proposed rate of 224g/ha Super(-1).
CAIP-WEBSITE, 2006. University of Florida. Center for Aquatic and Invasive Plants. APIRS. Landoltia punctata (Spirodela punctata) [Online Database]
Chaiprapat, S., Cheng, J.J., Classen, J.J., & S.K. Liehr. 2005. Role of Internal Nutrient Storage in Duckweed Growth for Swine Wastewater Treatment. Transactions of the ASAE. Vol. 48(6): 2247-2258
Koschnick, T.J., W.T. Haller & A.W. Chen. Carfentrazone-ethyl Pond Dissipation and Efficacy on Floating Plants. Journal of Aquatic Plant Management 42: 103.
Koschnick, T.J., Haller, W.T. & L. Glasgow. 2006. Documentation of Landoltia (Landoltia punctata) resistance to Diquat. Weed Science. Vol. 54, No. 4, pp. 615-619.
USGS. Nonindigenous Aquatic Species
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