Illustrated Guide to
of New Zealand
Weeds of New Zealand
by Ian Popay, Paul Champion & Trevor James
ISBN 0 473 09760 5
by kind permission of the
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.
of the publication Common Weeds of New Zealand must always
Available from Touchwood
aquatic perennial, with stems emerging above the water surface.
Leaves feather-like, finely divided. Forms dense mats floating on
the surface, or on damp ground. Occurs in shallow, still or slow-moving
freshwater less than 2.5 m deep.
- Flowers Minute,
without petals. Broadly-triangular white sepals 0.5 x 0.3 mm enclose
the four-ribbed ovary. Female flowers solitary in the axils of
aerial leaves. Male flowers (on different plants from the female
flowers) not seen in NZ. Flowers Sep-Feb.
- Fruit Not
set in NZ.
- Leaves Pale
bluish-green, up to 45 mm long by 15 mm wide, in whorls of five
or six. Finely-divided into 25-30 awl-shaped leaflets, each up
to 7 mm long.
- Stems Bluish-green,
up to 5 mm in diameter. Up to 2 m long, emerging up to 10 cm above
the surface. Submerged parts bare, with constricted nodes.
- Roots Appearing
at the lower stem nodes.
of peaty or organically rich swamps and drains, lake margins and
Locally common in scattered
NI localities in Auckland, Waikato, Wairarapa and southern Manawatu.
Originally from South America.
Listed on the National
Pest Plant Accord (see Introduction for details).
of botanical name
= many leaves, referring to the finely divided leaves; aquaticum
(Lat.) = growing in water.