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Oxygen Weed

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Oxygen weed
Oxgen weed - Photo by Rohan Wells; National Institute of Water and Atmospheric Research
Scientific Name: 

Lagarosiphon major (Ridley) Moss (ITIS)

Common Name: 

Oxygen weed, Lagarosiphon, African elodea, curly waterweed

Native To: 

Southern Africa (Bickel 2011)

Date of U.S. Introduction: 

Not introduced

Means of Introduction: 

Spread through the world by the aquarium trade (Bickel 2011)


Has invaded New Zealand and Europe. It can inhabit freshwater lakes, dams and slow moving streams. Forms dense mats that block sunlight, thereby killing native aquatic plant and animal species, which could rival the harmful effects of hydrilla (Csurhes and Edwards 1998)

Current U.S. Distribution: 
Not currently established

Federally Regulated

USDA. APHIS. Plant Protection and Quarantine.

Includes species listed as a Federal Noxious Weed under the Plant Protection Act, which makes it illegal in the U.S. to import or transport between States without a permit.


University of Georgia. Center for Invasive Species and Ecosystem Health.


Google. YouTube; RTÉ Ireland. Eco Eye.

This beautiful episode opens on Lough Corrib at sunrise. Anja sees first-hand the devastating and costly impacts of a new arrival to an existing ecosystem, Lagarosiphon Major a pond weed has taken hold in the waterbody. Part 1 of 4

Selected Resources

The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for Oxygen Weed.

IUCN. Species Survival Commission. Invasive Species Specialist Group.

Centre for Invasive Species Solutions; Atlas of Living Australia; Australian Government. Department of Agriculture, Water and the Environment.

Federal Government
International Government

New South Wales Department of Primary Industries (Australia).

State and Local Government

University of California. Weed Research and Information Center.

See also: Weeds in Natural Areas for more information sheets

University of Florida. IFAS. Center for Aquatic and Invasive Plants.