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Water lettuce
Common name:
Water lettuceScientific name:
Pistia stratiotes (Araceae)Alternative common names:
Nile cabbage, Nile lettuce, shell flower, water cabbage, water fern (English), Waterslaai (Afrikaans)
A free-floating, aquatic perennial plant seldom exceeding 150-200mm in diameter. The plants consist of a rosette of leaves and a tuft of long, fibrous roots beneath and it resembles floating lettuces. The leaves are pale yellow-green, narrower at the base and round, straight or notched at their tips, ribbed, with many longitudinal veins radiating from the base. The leaves are softly hairy on both surfaces. Small pale green or white flowers appear from February-May, but occasionally throughout the year in warm tropical climates and it produces small, green capsules. The leaves are poisonous and known to cause intense internal irritation. It invades dams, pans and slow-moving rivers in subtropical regions.
Additional Info
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Where does this species come from?
South America (Brazil)What is its invasive status in South Africa?
Existing legislation: CARA 2002 – Category 1 NEMBA – Category 1bWhere in South Africa is it a problem?
KwaZulu-Natal, Eastern Cape and MpumalangaHow does it spread?
Spreads and reproduces by seeds and rhizomesWhy is it a problem?
Forms dense mats which completely cover a water surface. The mats clog waterways and irrigation equipment, reduce waterflow, impede navigation, fishing and other recreational activities, provides a breeding place for mosquitoes and bilharzia-carrying snailsWhat does it look like?
General description: A free-floating, aquatic perennial plant seldom exceeding 150-200mm in diameter. The plants consist of a rosette of leaves and a tuft of long, fibrous roots beneath and resemble floating lettuces. Leaves: Pale yellow-green, narrower at the base and round, straight or notched at their tips, ribbed, with many longitudinal veins radiating from the base. The leaves are softly hairy on both surfaces. Flowers: Small pale green or white flowers appearing from February-May, but occasionally throughout the year in warm tropical climates. Fruit/Seeds: Produces small, green capsulesDoes the plant have any uses?
Used as an aquatic ornamentPlant me instead alternatives
Small yellow waterlily (Nymphoides thunbergiana), Cape pond weed (Aponogeton distachyos)
General News Updates
2019 National Symposium on Biological Invasio…
26-02-2019
This is your invitation to South Africa's 2019 National Symposium on Biological Invasions. The convention is hosted by the Centre for Invasion Biology (CIB), University of Stellenbosch, and the Biolo... Read more
2019 Invasive Species Training
22-01-2019
During the past five years (2014-2018), ISSA invasive species trainers have trained 4 000 in the identification of invasive species and laws pertaining to invasive species across South Africa. ... Read more
Alien Grass Working Group
04-09-2018
Who are we? The South African National Alien Grass Working Group was jointly initiated by the South African Biodiversity Institute (SANBI) and the Centre for Excellence in Invasion Biology (C·I·B) in... Read more
Permits for planting indigenous Cynodon?
01-03-2018
On 16 February, 2018, South Africa's Department of Environmental Affairs issued amendments to the regulations and lists relating to the National List of Invasive Species. Updates to the draft&n... Read more
Invasive species training 2018 dates released
28-02-2018
Interested in invasive species? How much do you know about NEMBA invasive species compliance for landowners and organs of state? The South African Green Industries Council (SAGIC) have released... Read more
Communications post for Africa advertised
25-01-2018
The Nature Conservancy has advertised a brand new post: Communications Manager, Africa Region. Knowledge of invasive species and water would be an asset in this post. See details below: Job Titl... Read more
Atlantis Aquifer Invasive Plant Control
The Nature Conservancy Director of Water Funds for South Africa, Louise Stafford, is inviting invasive species teams, mentors and experts to submit proposals for an invasive species clearing project in Atlantis, Western Cape. The…
Xhosa names for invasive plants
46 Xhosa names for invasive plants have been identified by the Selmar Schonland Herbarium, Rhodes University Botany Department, Grahamstown, Eastern Cape. The first list of Xhosa names for plants was compiled…
Removal of invasive vegetation at Wemmershoek Dam will help City save water
"Enormous progress has been made on removing invasive alien vegetation in the catchment area around Wemmershoek Dam", says Executive Mayor, Patricia de Lille, City of Cape Town. "Invasive alien vegetation around…
Invasive species clearing campaign in Jukskei Park
Johannesburg City Parks and Zoo launched National Invasive Species Week initiatives on Thursday 12 October, 2017 in Juweel Park, Jukskei Park, Randburg, Gauteng. National Invasive Species Week is an awareness campaign…
Sign up for Invasive Species Training this November ...
The last two sessions of SAGIC Invasive Species legislation and herbicide applicator’s course in 2017 will take place in November. Are you interested in flora and fauna? How much do you…
