Potamogeton crispus
Common name
curly pondweed
Family
Potamogetonaceae
Flora category
Vascular – Exotic
Structural class
Herbs - Monocots
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
POTCRI
Brief description
Submerged aquatic plant that has green to red/brown leaves arranged alternately on stems. the leaves are ca 10mm in width and up to 80 mm long with distinct wavy edges (hence the name ‘crispus’). Centre veins of the leaves are normally reddish.
Distribution
Widely naturalised throughout New Zealand, rare in West Coast Region
Habitat
Moderately fast flowing to still water bodies.
Features
Entirely submerged, bottom-rooting, normally perennial. Slender rhizomes and roots. P. crispus has long branched stems, that feels slightly flattened (as opposed to round or cylindrical), with submerged leaves that are arranged alternately on the stem. The leaves are green to reddish brown, slightly translucent, about 10mm in width, and up to 80mm long. Leaf margins are markedly wavy and crimped, with fine teeth near the tip. Centre veins of the leaves are normally reddish. The inflorescence spike has few flowers. Flowers small, green, on spikes up to 1 cm long, 4 flat dark seeds. The fruit (achenes) are large (4mm) and thick, with a curved beak and a toothed (rounded toothed) dorsal keel. Turions or winter buds of hard scales formed by shortened, thickened leaves with broad and strongly toothed bases.
Similar taxa
Potamogeton ochreatus and P. cheesemanii. P. ochreatus has a straight edged leaf and a blunt leaf tip, whereas curled pondweed has a rounded leaf tip with crimped edges. It can be distinguished from P. cheesemanii by the submerged leaves, which are narrower and much more crimped in curled pondweed.
Flowering
November, December, January
Flower colours
Cream, Green
Fruiting
Autumn
Life cycle
Spread by seeds, stem fragments, rhizomes, or turions. Birds disperse seed, fragments, rhizomes and turions dispersed by contaminated machinery and water movement.
Year naturalised
1940
Origin
Native to Europe, Asia, Africa and Australia.
Reason for introduction
Ornamental pond and aquarium plant
Control techniques
Not usually controlled in New Zealand, but may be controlled manually, or mechanically.
Tolerances
Tolerates brackish, flowing or still water, and grows to 10 m depth.
Etymology
potamogeton: River dweller
Attribution
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA).
References and further reading
Champion et al (2012). Freshwater Pests of New Zealand. NIWA publication. http://www.niwa.co.nz/freshwater-and-estuaries/management-tools/identification-guides-and-fact-sheets/freshwater-pest-species.
Johnson PN, Brooke PA (1989). Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319pp.
Coffey BT, Clayton JS (1988). New Zealand water plants: a guide to plants found in New Zealand freshwaters. Ruakura Agricultural Cente. 65pp.
Aston, H (1977). Aquatic plants of Australia. Melbourne University Press, 367pp.