Species

Myriophyllum variifolium

Etymology

Myriophyllum: many leaves

Authority

Myriophyllum variifolium Hook. f.

Family

Haloragaceae

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.

Flora Category

Vascular - Exotic

Distribution

Locally naturalised, Hunua Range, Auckland and Opawa River, Marlborough.

Habitat

Still and slow flowing water bodies.

Features

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

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.

Life Cycle and Dispersal

Stem fragmentation and lateral stem growth. It does not produce viable seed in New Zealand, with only female flowers known from field sites.

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.

This page last updated on 21 Aug 2013