Species

Callitriche platycarpa

Etymology

Callitriche: From the Greek kalli 'beautiful' and thrix 'hair', referring to the beautiful stems

Authority

Callitriche platycarpa Kütz

Family

Plantaginaceae

Brief Description

An erect amphibious, slender-stemmed perennial, growing up to 1m tall in shallow freshwater or creeping, prostrate and mat-like on damp ground. Apical rosettes of leaves frequently float on the water surface, submerged leaves narrow. The flowers are small, green and inconspicuous.

Flora Category

Vascular - Exotic

Structural Class

Dicotyledonous Herbs other than Composites

Distribution

Plalmerston North in drains.

Habitat

Shallow water lake margins and slow flowing streams.

Features

The stems are threadlike and branched, up to ca 50 cm long. The leaves are opposite and may be submerged or floating. Submerged leaves are narrow 0.5 to 2.5cm long with 2 rounded leaf tip lobes. The floating leaves are oval (ca 1 cm wide), and may form rosettes on the water surface. The leaf bases are joined by a wing-like ridge. The flowers are small, without petals and sepal, but have 2 small white bracts (that act as petals). The flowers occur in the leaf bases. There are 4 tiny fruits per flower that are heart shaped ca. up to 1mm in size, and do not have a narrow winged margin.

Similar Taxa

All Callitriche species are superficially similar and have variable vegetative parts (Lansdown 2008). Very similar to C. stagnalis only distinguished reliably by pollen characters (Lansdown 2008).

Flowering

Spring/summer

Flower Colours

Green

Fruiting

Summer to autumn

Year Naturalised

1989

Origin

Native to Europe.

Reason for Introduction

Probably a soil seed contaminant or contaminant of ornamental pond plants.

Control Techniques

Can be controlled manually, mechanically or herbicidally depending on situation.

Life Cycle and Dispersal

Plant fragments and seed.

Tolerances

The taxonomy of the four introduced Northern Hemisphere Callitriche requires further investigation in New Zealand.

Attribution

Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA).

References and further reading

Johnson PN, Brooke PA (1989).  Wetland plants in New Zealand.   DSIR Field Guide, DSIR Publishing, Wellington. 319pp.

Aston, H (1977).  Aquatic plants of Australia. Melbourne University Press, 367pp.

Lansdown, R.V. (2008). Water-starworts (Callitriche of Europe) BSBI Handbook 2, London. 180 pp.

This page last updated on 21 Aug 2013