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(Glossostigma cleistanthum)

Photo of mudmat
Photo credit: Leslie J Mehrhoff, University of Connecticut,

A tiny fast-growing aquatic plant that can tolerate a wide range of conditions. It is commonly grown in the aquarium trade and could threaten natural areas if released.

 Overview map of prohibited classification in WI
Prohibited (red) counties

Other names for this plant include:

This plant has been misidentified in other regions as Glossostigma diandrum and has not been extensively searched outside the northeastern United States. It may be underreported.

Classification in Wisconsin: Prohibited

Ecological Threat
  • Reported as a speedy rate of growth and likely to survive cold winters.
  • Probably introduced to the US as an aquarium plant, then released into natural environments. It could be easily spread by waterfowl.
  • Unlike many other wetlands or aquatic invasive plants, mudmat can invade undisturbed, natural environments.

Leaves: Extremely tiny, bright green leaves grow no larger than 1-2 cm. They are linear-based with broader tips.

Flowers: If submerged, tiny, cleistogamous (self-contained/pollinating) flowers are produced, but if stems are emergent, the plants have small, white, open flowers.

Fruits & seeds: Small capsules are produced that carry seeds. Due to its dense growing habit, thousands of seeds can be made from one square meter of plants.

Stems: Creeping stems grow horizontally below the soil surface and root at the nodes.

Similar species: This plant might be confused with other tiny aquatic creeping plants, particularly in the Limosella or Utricularia families.


Currently, there have been no reports of mudmat in Wisconsin Have you seen it? Please send us a report.


Mechanical: Little is documented about controlling this plant. It can spread from fragments so care must be taken to collect and destroy all parts of the plant if pulled.

Chemical: Although little information is documented, registered aquatic herbicides might provide some control. Application of aquatic herbicide requires a permit.

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