Species

Gymnocoronis spilanthoides

Common Name(s)

Senegal tea

Authority

Gymnocoronis spilanthoides (D. Don) DC.

Family

Asteraceae

Brief Description

Sprawling emergent perennial herb, becoming upright when flowering. Leaves are dark green, opposite, and ovate to lanceolate in shape. They vary in size from 5 to 20 cm long, 2.5 to 5 cm wide, and are on shortish stalks. Leaf margins are serrate and slightly wavy. Flowers are whitish, numerous and highly scented.

Flora Category

Vascular - Exotic

Structural Class

Dicotyledonous Herbs - Composites

Habitat

Aquatic: Emergent. The plant grows in wet marshy soils and at water margins, Plant grows in wetland communities in still or flowing water.

Features

Perennial aquatic herb to 1+ m high. Roots finely fibrous, also aerially from stem nodes. Stems erect at first, becoming prostrate, branching and rooting at nodes, 1-1.5 m long, 5-10 mm diam at first, to 20 mm with age, hollow, inflated, floating. Leaves paired with opposite stalks joined at stem, 50-200 x 25-50 mm, lance-shaped, dark green, serrate, slightly wavy. Flowerhead clover-like, with many thin white florets, Nov-Apr. Seed yellow-brown, 5 mm diam. Plant dormant over Winter, dies back to rootstock if chilled, resprouts in Spring.

Similar Taxa

Is similar to Alternanthera philoxeroides (alligator weed) when in its sprawling phase but can be differentiated from alligator weed by its narrower leaves with serrated margins and reddish tinge. G. spilanthoides also has clusters of flowers.

Flowering

December, January, February, March, April, May.

Flower Colours

White

Fruiting

summer/autumn

Year Naturalised

1991

Origin

South America.

Reason for Introduction

Ornamental aquarium and pond plant. Was sold in the aquarium trade as costata.

Control Techniques

Notify regional council if found

Life Cycle and Dispersal

Perennial. Plants are dormant in winter, producing shoots in spring from protected buds in the nodes and crown. Reproduces sexually by seed. Vegetative reproduction occurs through the production of roots at stem nodes and vegetative fragmentation. Seed stems and root fragments are dispersed in water, on livestock hooves and machinery. Can also be spread by dumped aquaria contents when liberating fish.

Tolerances

The plant is tolerant to shade, frost and poor drainage and intolerant to drought.

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