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Blunt-fruited Water Starwort

Callitriche obtusangula

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Plant Profile

Flowering Months:
Callitrichaceae (Water Starwort)
Life Cycle:
Maximum Size:
30 centimetres tall
Marshes, mud, water, wetland.

Green, no petals
Minute, green, petalless flowers, hardly noticeable. The male flowers have yellow anthers.
Globular fruits which are broadly winged, up to 2mm across. Grows only in still water. The water is often limy.
Yellowish-green, linear leaves. The leaves can be either floating or submerged. The floating leaves are broadly diamond-shaped.
Other Names:
Blue-fruited Water-starwort.
Frequency (UK):
Occasionally seen  

Similar Species

Other Information


Callitriche obtusangula is a species of plants belonging to the genus Callitriche, commonly known as blunt-fruited water-starwort or blue-fruited water-starwort. It is native to Europe, Northwest Africa, and Southwest Asia, but has also been introduced to North America. It is typically found growing in still or slow-flowing mesotrophic to eutrophic waters, and can even tolerate brackish water. It is a perennial herb that can reach a height of up to 30 cm. The leaves are oppositely arranged, lance-shaped, and up to 13 cm long. The flowers are white with four petals and grow in spikes. The fruits are small, oval-shaped nuts.


Blunt-fruited Water Starwort (Callitriche obtusangula) is a plant species belonging to the Callitrichaceae family. It is a floating aquatic plant that is native to temperate regions of Europe, Asia and North America.

This plant is characterized by its small, oval-shaped leaves that are typically green in color and arranged opposite each other along the stem. The stems are thin and flexible, allowing the plant to float on the water's surface. The flowers of the Blunt-fruited Water Starwort are small, inconspicuous, and often green or yellow in color.

Blunt-fruited Water Starwort is commonly found in slow-moving or still bodies of water, such as ponds, lakes, and marshes. It prefers shallow waters with a mud or muck bottom and can tolerate a wide range of water conditions, from fresh to brackish.

The plant is a valuable source of food and habitat for a variety of aquatic species, including waterfowl, fish, and insects. It also helps to maintain the health of aquatic ecosystems by absorbing excess nutrients and reducing algae growth.

Blunt-fruited Water Starwort is considered a weed in some regions, particularly in the United States, where it can outcompete native aquatic plants and disrupt the balance of aquatic ecosystems. However, it is not considered invasive in Europe.

Blunt-fruited Water Starwort is a versatile floating aquatic plant that provides important ecological benefits and supports a variety of aquatic species. Despite being considered a weed in some regions, it is still an important part of many aquatic ecosystems.

Blunt-fruited Water Starwort is a very hardy plant that is able to adapt to a wide range of growing conditions. It can grow in both full sun and partial shade, and can tolerate water temperatures ranging from cold to warm. This makes it an ideal plant for use in pond and aquarium environments, where it can help to improve water quality and provide habitat for aquatic life.

In addition to its ecological benefits, Blunt-fruited Water Starwort is also commonly used for ornamental purposes. Its small size and delicate appearance make it an attractive addition to water gardens, pond edges, and aquariums. In addition, its floating habit allows it to add interest to the surface of the water, providing a unique and visually appealing contrast to the underwater foliage.

One of the most attractive features of Blunt-fruited Water Starwort is its ability to spread rapidly and cover large areas of water. This can make it ideal for use in large ponds or lakes, where it can provide a lush and attractive coverage that helps to reduce sunlight penetration and improve water quality.

Blunt-fruited Water Starwort is a versatile and hardy plant that provides a wide range of benefits in aquatic environments. Its ecological importance, ornamental appeal, and ability to cover large areas of water make it a valuable addition to any water garden, pond, or aquarium. Whether used for its ecological benefits, ornamental purposes, or both, Blunt-fruited Water Starwort is a plant that is sure to impress.

Blunt-fruited Water Starwort is a very easy plant to care for, making it a great option for both experienced and novice pond or aquarium enthusiasts. In the wild, it will typically spread on its own, but in a managed pond or aquarium setting, it may need to be trimmed periodically to keep it from spreading too much.

To establish Blunt-fruited Water Starwort in a pond or aquarium, simply place the plant in the desired location and allow it to float freely. Over time, the plant will spread and cover the surface of the water, providing a beautiful and functional addition to the aquatic environment.

Blunt-fruited Water Starwort is also a very low-maintenance plant that does not require any special care or attention. It does not require fertilizer or special water conditions, and will grow in most types of water, from fresh to brackish. However, it is important to monitor the plant for any signs of disease or pest infestations, and to address any issues promptly to prevent them from spreading.

In addition to its ease of care, Blunt-fruited Water Starwort is also a very economical option for adding interest to a pond or aquarium. This is because the plant can be purchased in bulk and will spread on its own, providing a large coverage of floating foliage without the need for additional plants.

In conclusion, Blunt-fruited Water Starwort is a great option for anyone looking to add interest and beauty to their pond or aquarium. Its ease of care, low maintenance requirements, and economical cost make it a popular choice for both experienced and novice pond or aquarium enthusiasts. Whether used for its ecological benefits, ornamental appeal, or both, Blunt-fruited Water Starwort is a plant that is sure to impress.

Distribution Map

Reproduced by kind permission of the BSBI.

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