Dispersal: Seed, vegetative

Distribution from the Australasian Virtual Herbarium. CC-BY 3.0 AU
Distribution from the Australasian Virtual Herbarium. CC-BY 3.0 AU
 Recognition
  • an aquatic plant, either forming a rounded bush or a tangled mass of vegetation along waterways.
  • its stems (up to 20 mm thick) are hollow between the joints and its leaves are arranged in opposite pairs.
  • these leaves are somewhat elongated in shape (4-20 cm long and 1.5-8 cm wide) and have toothed margins.
  • its flower-heads are fluffy in appearance (12-20 mm across), white or pale purplish-white in colour, and arranged in small dense clusters at the tips of the leafy branches.
  • its yellowish-brown 'seeds' (about 5 mm long) are ribbed and hairless.
 Images
Image: Trevor James © Trevor James
Image: Trevor James © Trevor James
Image: P.B. Heenan © Landcare Research 2012
Image: P.B. Heenan © Landcare Research 2012
Image: Trevor James © Trevor James
Image: Trevor James © Trevor James
Weeds Key – interactive key to the weed species of New Zealand
 References
Biosecurity New Zealand 2012: Regional Pest Management Strategies Database. http://www.biosecurityperformance.maf.govt.nz/
Biosecurity New Zealand 2008: National Plant Pest Accord. MAF Biosecurity New Zealand, Wellington.
Howell, C. 2008: Consolidated list of environmental weeds in New Zealand. DOC Research & Development Series 292: 42.
Ministry for Primary Industries 23 Feb 2017: Unwanted Organisms Register. Version 02.01.02. https://www1.maf.govt.nz/uor