Myriophyllum variifolium
Family
Haloragaceae
Flora category
Vascular – Exotic
Structural class
Herbs - Dicotyledons other than Composites
Conservation status
Not applicable
Brief description
Sprawling emergent perennial herb with bright green needle like foliage like a small pine tree Submerged leaves are finely divided and pale green in colour.
Distribution
Locally naturalised, Hunua Range, Auckland and Opawa River, Marlborough.
Habitat
Still and slow flowing water bodies.
Detailed description
The emergent leaves are in whorls of 5-6 and are usually entire, although the lower leaves may have a few teeth. The submerged leaves have up to 19 elongated and widely spaced leaflets.
Similar taxa
Myriophyllum propinquum has reddish stems and leaves are arranged in whorls of 3-4, whereas M. variifolium has whorls of 5-6.
Flowering
November to February
Flower colours
White
Fruiting
None produced
Life cycle
Stem fragmentation and lateral stem growth. It does not produce viable seed in New Zealand, with only female flowers known from field sites.
Year naturalised
1990
Origin
Australia
Reason for introduction
Ornamental aquarium and pond plant.
Control techniques
Can be controlled manually, mechanically or herbicidally depending on situation.
Etymology
myriophyllum: Many leaves
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.