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Book cover - Common Weeds of New ZealandAn Illustrated Guide to
Common Weeds
of New Zealand


Lagarosiphon major


Reproduced from
Common Weeds of New Zealand
by Ian Popay, Paul Champion & Trevor James
ISBN 0 473 09760 5
by kind permission of the
New Zealand Plant Protection Society

Publication or other use of images or descriptive text on these pages is unauthorised unless written permission is obtained from the authors and publisher.
Appropriate acknowledgement of the publication Common Weeds of New Zealand must always be given.

Available from Touchwood Books

Lagarosiphon major - lagarosiphon

Lagarosiphon major - lagarosiphonWholly submerged, vigorous freshwater perennial up to 4 m tall, growing from depths of up to 6 m. One of the oxygen weeds.

  • Flowers Pink, minute, 0.25 mm in diameter and up to 6 cm long, threadlike, singly in axils of upper leaves, female only in NZ. Flowers Jan.
  • Fruit Does not seed in NZ, reproduces vegetatively by stem fragments.
  • Leaves Alternate along the stem, but closely-spaced, overlapping and curled backwards. Dark green, up to 16 mm long by 2 mm wide. Crowded towards the tips of the stems, more spaced below.
  • Stems Fragile, slender, 3 mm thick, much-branched.
  • Roots Fibrous.


Clear, still or slow-moving, low fertility freshwater of ponds, lakes, streams and rivers.


Scattered throughout NI, more local in SI. Originally from South Africa.


The oxygen weeds include Egeria, Elodea and Lagarosiphon. In Lagarosiphon, the leaves are spirally arranged, not in whorls, and are 16 mm long, stiff and strongly recurved. The flowers are small, pink and float on the water surface. Lagarosiphon is similar to Elodea, but is stiffer and larger, with longer stems. Listed on the National Pest Plant Accord (see Introduction for details).

Derivation of botanical name

Lagarosiphon (Gr.) = thin tube, the narrow perianth tube; major (Lat.) = larger.

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Web-notes: Weed Links

On this site

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External Links

WeedbustersWeedbusters New Zealand
Weedbusters is a weeds awareness and education programme that aims to protect New Zealand's environment from the increasing weed problem.
A free tool to assist farmers and agricultural professionals in decision-making regarding weed and pest identification, biology, impact and management.
Weed keyNew Zealand Weeds Key
An interactive identification key to the weeds of New Zealand. Developed at Landcare Research.

New Zealand Plant Conservation Network naturalised plants
Search for information on more than 2500 naturalise and weedy plants.
NZ Plant Protection SocietyNew Zealand Plant Protection Society
Their main objective: "To pool and exchange information on the biology of weeds, invertebrate and vertebrate pests, pathogens and beneficial organisms and methods for modifying their effects."
Massey UniversityMassey University Weeds Database
A site providing information about New Zealand weeds and weed control. It has a series of pages showing pictures of New Zealand weeds, notes on identification and control. It also provides information on a university paper entitled Controlling Weeds.

Weeds in Australia
Weeds website of the Australian Government.
Weed Society of Victoria
Promoting wider awareness and interest in weeds and their management. Includes a useful page of links to other weed societies.
Tamar Valley Weeds Strategy
Listing of common and botanical names, images, and information including control methods for weeds found in Tasmania, and also weeds of national significance.

Invasive and Exotic Species of North America
Images and other information from the University of Georgia.

World of Weeds
Weed-related resources including weed science, practical tools, gardening tips about controlling weeds, and environmental news updates.
Invasive Species Specialist Group
"The ISSG aims to reduce threats to natural ecosystems and the native species they contain by increasing awareness of invasive alien species, and of ways to prevent, control or eradicate them."
Site that includes a comprehensive collection of weed images from around the world.

FetchBook.Info Home PageBooks on Weeds from FetchBook.Info

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Last updated: July 13, 2014