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Rootless Duckweed

Wolffia arrhiza

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:
(in flower all year round)
Lemnaceae (Duckweed)
Life Cycle:
Maximum Size:
1 centimetre tall
Ditches, ponds, water.

White, no petals
Small, white, petalless flowers. Never flowers in the British Isles.
Fruits are never produced in the British Isles. They are small and insignificant.
A floating, aquatic perennial plant which is the world's smallest vascular plant.
Other Names:
Asian Watermeal, Least Duckweed, Spotless Watermeal.
Frequency (UK):
Rarely seen  

Other Information


Wolffia arrhiza, also known as Asian watermeal or rootless duckweed, is a species of aquatic plant in the duckweed family. It is native to Asia, and it has been introduced to other parts of the world. Wolffia arrhiza 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. Wolffia arrhiza 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.


Rootless Duckweed, also known as Wolffia arrhiza, is a species of floating aquatic plant that belongs to the Lemnaceae family. This tiny plant is native to Southeast Asia and is found in a wide range of water bodies such as ponds, lakes, and slow-moving streams. Its size and unique features have made it an interesting subject for many biologists and botanists.

Wolffia arrhiza is an interesting plant due to its tiny size, being one of the smallest flowering plants in the world. The plant measures just 0.5 to 1.2mm in width and length, making it nearly invisible to the naked eye. Despite its small size, it has a simple but elegant structure, with a single, small rootless leaf that floats on the surface of the water. The leaf is green in color and contains chloroplasts, allowing it to carry out photosynthesis.

One of the most remarkable features of Wolffia arrhiza is its ability to reproduce quickly and efficiently. The plant has the ability to produce new plants from a single cell, meaning that it can reproduce asexually. This makes it possible for the plant to grow and spread rapidly, creating dense colonies in a short amount of time. The tiny plant also produces tiny flowers, which are not often seen, but play a crucial role in the plant's reproduction.

In addition to its unique features, Wolffia arrhiza also has practical applications. The plant is an excellent source of protein, with a protein content of up to 40%. It is also rich in essential amino acids, making it a valuable food source for humans, livestock, and fish. In some countries, the plant is used as a traditional food ingredient, and it is also grown commercially for use in animal feed and as a food source for humans.

Rootless Duckweed, Wolffia arrhiza, is a tiny but fascinating aquatic plant that has been the subject of much study and research. Its tiny size, quick reproduction, and practical applications make it an interesting subject for both scientists and the general public. Whether you are a botanist, a biologist, or simply someone interested in nature, Wolffia arrhiza is sure to capture your imagination.

Aside from its potential as a food source, Wolffia arrhiza also has other practical uses. For example, it can be used as a natural filter for water bodies, as it is known to absorb and remove excess nutrients and pollutants from the water. This makes it a valuable tool for managing water quality, especially in aquaculture and fish farming operations.

Wolffia arrhiza is also of great interest to researchers in the field of phytoremediation. Phytoremediation is the use of plants to remove environmental contaminants from soil, water, or air. Wolffia arrhiza has been shown to have the ability to remove heavy metals, such as lead, from contaminated water. This makes it a promising tool for cleaning up contaminated water sources, as well as a way to protect aquatic life from the harmful effects of heavy metal pollution.

In addition, Wolffia arrhiza has been the subject of research in the field of biorefineries. A biorefinery is a facility that uses biomass as a raw material to produce a variety of products, including fuels, chemicals, and materials. Wolffia arrhiza has been identified as a potential raw material for the production of biofuels, as it can be grown quickly and efficiently using a variety of water sources.

Wolffia arrhiza is a unique and fascinating aquatic plant that has many practical uses. Its ability to remove pollutants from water, its potential as a food source, and its use in biorefineries are just a few examples of the many ways in which this tiny plant can be used for the benefit of society. Whether you are a researcher, a farmer, or simply someone interested in the natural world, Wolffia arrhiza is sure to pique your interest and inspire new ideas.

Wolffia arrhiza is also an important part of aquatic ecosystems and provides many benefits to the surrounding environment. The plant serves as a habitat for a variety of small aquatic animals, such as insects and snails, and also provides food for a range of species, including fish and waterfowl. By maintaining a healthy population of Wolffia arrhiza, the overall health and biodiversity of aquatic ecosystems can be improved.

In addition, Wolffia arrhiza is a great tool for managing water levels in a variety of water bodies. The plant has the ability to absorb and store water, which can help to regulate water levels in times of drought or heavy rainfall. This makes it an important tool for flood control, especially in areas that are prone to seasonal floods.

Wolffia arrhiza is also an important part of traditional cultures in many parts of Southeast Asia. The plant has a long history of use as a food source, and it is still commonly consumed in many rural communities. In some cultures, Wolffia arrhiza is also used in traditional medicine, and is believed to have a range of health benefits, such as improving digestion and treating skin conditions.

In conclusion, Wolffia arrhiza is much more than just a tiny floating plant. It is an important part of aquatic ecosystems, has a range of practical uses, and is an important part of traditional cultures in many parts of the world. Its versatility and versatility make it a fascinating subject of study, and it is sure to continue to be of interest for many years to come.

Distribution Map

Reproduced by kind permission of the BSBI.

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