Horned Poolmat
VUVulnerable

Horned Poolmat

Zannichellia palustris

**Horned Poolmat (Zannichellia palustris)** The Horned Poolmat is a submerged aquatic flowering plant characterized by its thread-like stems and narrow, linear leaves that grow in opposite pairs. The species produces small, inconspicuous flowers and distinctive horn-shaped fruits that give it its common name.

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Countries

Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Zannichellia_palustris

01Classification

Taxonomy & Classification

Kingdom

Plantae

Phylum

Tracheophyta

Class

Liliopsida

Order

Alismatales

Family

Potamogetonaceae

Genus

Zannichellia

Horned Poolmat belongs to the family Potamogetonaceae, order Alismatales, within the Liliopsida class.

02Description

Species Profile

**Horned Poolmat (Zannichellia palustris)** The Horned Poolmat is a submerged aquatic flowering plant characterized by its thread-like stems and narrow, linear leaves that grow in opposite pairs. The species produces small, inconspicuous flowers and distinctive horn-shaped fruits that give it its common name. As a fully aquatic plant, it plays a crucial role in freshwater ecosystems by providing oxygen, stabilizing sediments, and offering habitat and food for waterfowl, fish, and invertebrates. This cosmopolitan species demonstrates remarkable geographic distribution, occurring across six continents from Arctic regions to tropical zones. It inhabits shallow freshwater environments including ponds, lakes, slow-moving streams, ditches, and temporary pools. The plant tolerates varying salinity levels and can survive in both permanent and seasonal water bodies. Despite its wide distribution, Zannichellia palustris faces mounting pressures that have led to its Vulnerable status. Habitat degradation through wetland drainage and conversion represents a primary threat. Water pollution from agricultural runoff and urban development degrades water quality, while climate change affects the seasonal water cycles many populations depend upon. Infrastructure development continues to eliminate suitable habitat across its range. Conservation efforts vary by region but generally focus on wetland protection and restoration programs. Several countries have included the species in national biodiversity action plans, and some populations benefit from protected area designations. Water quality improvement initiatives indirectly support habitat conservation. The species' current trajectory remains uncertain due to insufficient population monitoring across its extensive range. While its wide distribution provides some resilience, continued habitat loss and degradation pose ongoing challenges to long-term population stability.

Horned Pondweed (Zannichellia palustris) faces significant threats from habitat degradation and loss due to water pollution, eutrophication, and wetland drainage for agricultural and urban development. The species is particularly vulnerable to changes in water quality and hydrological regimes that affect its shallow aquatic habitats.

Key Facts

IUCN StatusVulnerable (VU)
GroupPlants
03Habitat

Habitat & Distribution

FRESHWATERMajor
04Threats

Threats

Water pollution and eutrophication

HighOngoing

Wetland drainage and habitat loss

HighOngoing

Agricultural runoff and chemical contamination

MediumOngoing

Climate change affecting water levels

MediumOngoing

Urban development and water management changes

MediumOngoing
07National Status

National vs Global Threat Status

How this species is assessed at the national level compared to its IUCN global status (VU).

CountryNational StatusGlobal StatusComparison
EULCLeast ConcernVUVulnerableLower local risk
EULCLeast ConcernVUVulnerableLower local risk

National Red List data sourced from the National Red List Project (nationalredlist.org, ZSL) and country-specific Red List authorities.

Community

Community Sightings

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07Sources

Sources & Attribution

How to Cite

IUCN: IUCN (2025). The IUCN Red List of Threatened Species. Version 2025-1. Available at: https://www.iucnredlist.org. doi:10.2305/IUCN.UK.2025-1.RLTS

GBIF: GBIF.org (2025). GBIF Home Page. Available at: https://www.gbif.org

National Red Lists: ZSL (2025). National Red List. Zoological Society of London. Available at: https://www.nationalredlist.org

This page: SpeciesRadar (2025). Horned Poolmat (Zannichellia palustris). SpeciesRadar: Intelligence for Earth's Biodiversity. Available at: https://speciesradar.org/species/horned-poolmat

Full citation guide & data usage terms