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Greater Duckweed

Spirodela polyrhiza

Please keep in mind that it is illegal to uproot a plant without the landowner's consent and care should be taken at all times not to damage wild plants. Wild plants should never be picked for pleasure and some plants are protected by law.
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Plant Profile

Flowering Months:
Lemnaceae (Duckweed)
Life Cycle:
Maximum Size:
2 centimetres tall
Ditches, ponds, water.

White, no petals
Tiny, white and minute. Rarely produced.
Fruits are small, insignificant and are rarely produced.
An aquatic perennial plant with the largest fronds (leaves) of any British Duckweed species. The dark green leaves are large, shiny and purplish beneath. Each leaf has between 5 and 11 veins and has tufted roots.
Other Names:
Common Duckmeat, Common Duckweed, Duckmeat, Giant Duckweed, Great Duckmeat, Great Duckweed.
Frequency (UK):
Occasionally seen  

Other Information


Spirodela polyrhiza, also known as common duckweed or great duckweed, is a species of aquatic plant in the duckweed family. It is native to North America, and it is widely distributed in the United States and Canada. Spirodela polyrhiza is a small, free-floating plant that grows in still or slow-moving bodies of water. It has a simple structure, with a single, oval-shaped leaf (thallus) that is attached to the water surface by a root-like stalk (stipe). The plant reproduces rapidly, and it can form dense mats on the surface of the water. Spirodela polyrhiza is an important food source for waterfowl and other animals, and it is also used in wastewater treatment and as a bioindicator of water quality.


Greater Duckweed, also known as Spirodela polyrhiza, is a tiny aquatic plant that can be found floating on the surface of freshwater ponds and slow-moving streams. Despite its small size, this plant plays a crucial role in maintaining a healthy aquatic ecosystem and has numerous benefits for the environment and human health.

Physical Characteristics of Greater Duckweed

Greater Duckweed is a small, round, green plant that measures only about 1-2 centimeters in diameter. It has a single, floating leaf that is covered with small hairs, giving it a velvety texture. The plant also has a root system that hangs down into the water, absorbing nutrients and minerals from the water column.

Ecological Importance of Greater Duckweed

Greater Duckweed is an important plant in aquatic ecosystems as it provides a habitat and food source for a variety of organisms. The plant serves as a habitat for microorganisms, small insects, and aquatic animals such as tadpoles and small fish. Additionally, it helps to reduce the amount of harmful pollutants in the water, such as nitrogen and phosphorus, by absorbing these nutrients and reducing the growth of harmful algae.

Uses of Greater Duckweed in Human Health and Agriculture

In addition to its ecological benefits, Greater Duckweed also has numerous benefits for human health and agriculture. The plant is a rich source of protein, carbohydrates, and essential amino acids, making it a potential food source for humans and livestock. Additionally, research has shown that extracts from Greater Duckweed have medicinal properties, such as anti-inflammatory, antioxidant, and antiviral effects, making it a promising candidate for use in traditional medicine.

In agriculture, Greater Duckweed can be used as a natural fertilizer. Its ability to absorb nutrients from the water makes it an effective tool for reducing nutrient runoff from farms, which can help to reduce the amount of harmful pollutants in water bodies. The plant can also be used to clean up contaminated water, such as wastewater from industrial processes or agricultural runoff, by removing harmful pollutants from the water.

Greater Duckweed is a small but mighty plant that has numerous benefits for both the environment and human health. Its ability to absorb pollutants and provide a habitat for aquatic organisms makes it an important component of healthy aquatic ecosystems, while its potential as a food source and medicine make it a valuable resource for human populations. With continued research, Greater Duckweed has the potential to be a major player in the fight against environmental degradation and in improving human health and well-being.

Cultivation of Greater Duckweed

The fast growth rate and ability to absorb nutrients make Greater Duckweed an attractive option for cultivation and commercial production. The plant can be grown in large ponds or tanks and requires minimal maintenance, making it a low-cost option for producing food and medicine.

Greater Duckweed can be harvested and processed into a variety of products, including animal feed, fertilizer, and traditional medicines. The plant is also being studied for its potential use as a biofuel, as its high starch content makes it a promising candidate for the production of bioethanol.

In addition to its practical applications, Greater Duckweed is also popular in aquariums and water gardens as an attractive and low-maintenance floating plant. Its small size and ability to spread quickly make it an ideal option for creating a dense carpet of vegetation on the surface of the water, providing a natural and aesthetically pleasing habitat for aquatic animals.

Potential Challenges in the Cultivation of Greater Duckweed

Despite its numerous benefits, the cultivation of Greater Duckweed does pose some challenges. The plant is highly invasive and can quickly spread out of control if not managed properly. In natural water bodies, it can compete with native vegetation, reducing biodiversity and altering the ecosystem.

Additionally, the process of harvesting and processing Greater Duckweed requires specialized equipment and a significant amount of labor, making it more difficult to produce on a large scale. However, with continued research and development, these challenges can be overcome, and the full potential of this plant can be realized.

Greater Duckweed is a versatile and valuable plant that has the potential to play a significant role in a sustainable future. From improving the health of aquatic ecosystems to providing a low-cost source of food and medicine, Greater Duckweed is a plant that should not be underestimated. With careful management and continued research, this tiny floating plant has the potential to make a big impact.

Potential Applications of Greater Duckweed in Bioremediation

In addition to its use as a food source, fertilizer, and medicine, Greater Duckweed is also being studied for its potential in bioremediation, or the use of living organisms to clean up contaminated environments. The plant's ability to absorb pollutants, such as heavy metals and toxic organic compounds, makes it a promising candidate for the treatment of contaminated water bodies.

Studies have shown that Greater Duckweed is effective in removing lead, cadmium, and other heavy metals from contaminated water. Additionally, the plant has been shown to reduce the concentration of toxic organic compounds, such as dioxins, in water bodies. The plant's ability to degrade these contaminants is due to its high metabolism and the presence of specialized enzymes in its tissues.

Potential applications of Greater Duckweed in bioremediation include the treatment of contaminated water from industrial processes and agricultural runoff, as well as the treatment of contaminated groundwater. The plant can be grown in large ponds or tanks, making it an effective and low-cost option for the treatment of contaminated water on a large scale.

Greater Duckweed and Climate Change

In addition to its potential in bioremediation, Greater Duckweed also has a role to play in mitigating the effects of climate change. The plant has a high growth rate, which allows it to absorb large amounts of carbon dioxide from the atmosphere, reducing the concentration of this greenhouse gas in the atmosphere.

Additionally, Greater Duckweed has a high starch content, making it a promising candidate for the production of biofuels. The use of biofuels can help to reduce the emission of greenhouse gases, such as carbon dioxide, into the atmosphere, slowing the rate of climate change.

In conclusion, Greater Duckweed is a versatile and valuable plant that has a role to play in addressing a variety of environmental and human health challenges. Whether it is used for food production, traditional medicine, bioremediation, or as a tool in the fight against climate change, Greater Duckweed is a plant that should not be overlooked. With continued research and development, the full potential of this tiny floating plant can be realized, making it a key player in a sustainable future.

Distribution Map

Reproduced by kind permission of the BSBI.

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