Species

Glyceria fluitans

Etymology

Glyceria: From the Greek glykos 'sweet'.
fluitans: From the Greek fluito (floating)

Common Name(s)

floating sweetgrass

Authority

Glyceria fluitans (L.) R.Br.

Family

Poaceae

Brief Description

Aquatic perennial emergent grass found on the margins of freshwaters on damp ground and swamps. It is characterised by its bright green leaf blades, and ability to form loose floating mats in shallow water.

Flora Category

Vascular - Exotic

NVS Species Code

GLYFLU

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.

Structural Class

Grasses

Distribution

Throughout New Zealand.

Habitat

Aquatic in drains and other slow flowing waterbodies. Damp ground in swamps and pastures, drains and river banks.

Features

Perennial marginal aquatic grass, loosely tufted or forming loose masses in shallow water. Culm (20)-45-75 cm. , erect or spreading, sometimes prostrate or floating at base. Leaf blade bright green 10-23 cm, folded at first then becoming flat. Panicle (20)-30-55 cm.

Similar Taxa

Very similar to Glyceria declinata. These two species can be distinguished when flowering as G. declinata has 3-5 distinct teeth on the lemma apex and the palea teeth exceed the lemma apex. G. fluitans has a rounded lemma and the palea does not exceed the lemma. G. maxima is a taller species, which has a distinct pointed ligule.

Flowering

Spring/summer.

Flower Colours

Green

Fruiting

late spring-autumn

Year Naturalised

1872

Origin

Europe and North America.

Reason for Introduction

Pasture species, or contamination of other grass seed

Control Techniques

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

Life Cycle and Dispersal

Perennial. Seed and vegetative fragment spread by water movement. Reproduces by seed and rhizomes. Each flower head consists of an open panicle with 20-30 spikelets containing many seeds. Seed and stem fragments spread within catchment via water flow. Contaminated diggers, livestock, soil movement, dumped vegetation, eel nets boats and trailers all spread seed and rhizomes into new catchments.

Tolerances

Tolerant of very damp ground, physical damage, grazing, cold temperatures, and high nutrient levels. Intolerant of shade.

Attribution

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

References and further reading

Coffey BT, Clayton JS (1988).  New Zealand water plants:  a guide to plants found in New Zealand freshwaters.  Ruakura Agricultural Cente. 65pp.

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

Champion et al (2010).  An illustrated guide to common grasses, sedges and rushes of New Zealand.  NZ Plant Protection Society Inc, 182pp.

This page last updated on 21 Aug 2013