Callitriche brutia
A dwarf amphibious herb that filters arsenic and resists environmental stress.
Callitriche brutia, called pedunculate water-starwort, is a small amphibious herb that can live for one year or many. It belongs to the genus Callitriche and is a dicotyledon. This plant takes over aquatic spots like wetlands, lakes, rivers, streams, and pools, and it does well in oligotrophic conditions—places with very few nutrients. First recorded in Ireland and England, it has become invasive because it resists environmental stress and can thrive in still water.
The plant is long, with many rounded leaves along its stem and a flower-like cluster of leaves at the top. It often grows in thick mats in one area, usually right in water or very wet ground.
Its habitat stretches across Europe, from temporary pools, lakes, and canals to fast-moving upland rivers. It also shows up in ditches, ponds, wetlands, shallow lake edges, and drains. It is most common in the uplands of Britain and Ireland, plus the New Forest in South Hampshire and the Lizard Peninsula in West Cornwall.
Callitriche brutia uses rhizofiltration for phytoremediation—its roots filter excess nutrients or toxic substances from wastewater, surface water, and contaminated groundwater. Submerged parts of the plant hold high levels of arsenic, around 523 mg/kg. Arsenic is a common metalloid found in rocks, minerals, soils, water, air, and living things, and it can take many chemical forms with different toxicity and mobility. Related species like Callitriche lusitanica and Callitriche stagnalis also act as phytoremediators for arsenic and uranium.
As both an annual and perennial, the plant can complete its life cycle in one season or live for years. It reproduces both asexually and sexually. Asexually, it uses fragmentation—pieces break off and grow into new plants. Sexually, it relies on pollination of male stamens and fertilization of female pistils to produce a zygote.
This aquatic herb has complex whorls of leaves without petioles. Its leaves show linear veins, and the stems are thick, smooth, and hairless. Flowers appear from May to September, are green, and have no petals.
Quick Facts
- Genus
- Callitriche
- Species
- brutia
Facts from the source article.
Lore & Background
Callitriche brutia is a long plant with many rounded leaves across its stem and a bundle of leaves at the top in a flower-like shape. It often grows in large amounts in a single area, directly in water or very damp areas. Its habitats range from ephemeral pools, lakes, and canals to fast-flowing upland rivers across Europe, and it is most abundant in the upland regions of Britain and Ireland, as well as areas in the New Forest (South Hampshire) and the Lizard Peninsula (West Cornwall).
The plant is known to use rhizofiltration during phytoremediation, a process in which excess nutrients or toxic substances are filtered out of waste water, surface water, and contaminated groundwater using a mass of roots. High concentrations of arsenic (As), about 523 mg/kg, are found submerged in Callitriche brutia. Similar species, such as Callitriche lusitanica and Callitriche stagnalis, also have arsenic and uranium phytoremediators.
Callitriche brutia reproduces both asexually, through fragmentation where broken fragments grow into whole new plants, and sexually, via pollination of the male stamen and fertilization of the female pistil to produce a zygote. It has complex-whorled leaves without petioles, linear veins, thick stems, and is smooth and hairless. Its flowers appear green with no petals.
Reader's Guide
Callitriche brutia is notable for its dual role as both an invasive species and a phytoremediator. Its resistance to environmental stressors and ability to grow in still water have allowed it to spread beyond its original range in Ireland and England, becoming invasive in new habitats. At the same time, its capacity for rhizofiltration—filtering toxic substances through its roots—makes it valuable for cleaning contaminated water. The plant accumulates high concentrations of arsenic (up to 523 mg/kg), a common metalloid found in rocks, minerals, soils, natural waters, the atmosphere, and organisms. This ability to absorb and store arsenic suggests potential use in bioremediation projects, particularly in wetlands or shallow waters where it thrives. However, its invasive nature requires careful management to prevent ecological disruption. The plant's life cycle as both an annual and perennial, combined with its dual reproductive strategies (fragmentation and sexual reproduction), contributes to its resilience and spread. Its presence in upland regions of Britain and Ireland, as well as specific areas like the New Forest and Lizard Peninsula, highlights its adaptability to diverse aquatic environments, from ephemeral pools to fast-flowing rivers.
Did You Know?
- Callitriche brutia can accumulate up to 523 mg/kg of arsenic in its submerged tissues.
- It reproduces asexually through fragmentation, where broken plant parts grow into new individuals.
- The plant flowers from May to September with green, petal-less flowers.
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