Species

Glyceria declinata

Etymology

Glyceria: From the Greek glykos 'sweet'.

Common Name(s)

blue sweet grass, glaucous sweet grass

Authority

Glyceria declinata Bréb.

Family

Poaceae

Brief Description

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

Flora Category

Vascular - Exotic

NVS Species Code

GLYDEC

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, including Stewart Island and Chathams.

Habitat

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

Features

Perennial marginal aquatic grass with rather flaccid culms (15)-25-45 cm. Leaf blade (4)-8-17 cm, folded at first then becoming flat. Panicle 20-30-(40)cm.

Similar Taxa

Very similar to Glyceria fluitans. 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.

Fruiting

late spring-autumn

Year Naturalised

1969

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. Seed is produced but is probably not viable for more than one season.

Tolerances

Can tolerate very damp ground, or swampy conditions.

Attribution

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

References and further reading

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

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.

 

This page last updated on 21 Aug 2013