Glyceria declinata
Common name
blue sweet grass, glaucous sweet grass
Family
Poaceae
Flora category
Vascular – Exotic
Structural class
Grasses
NVS code
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.
GLYDEC
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.
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
Life cycle
Perennial. Seed and vegetative fragment spread by water movement. Seed is produced but is probably not viable for more than one season.
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.
Tolerances
Can tolerate very damp ground, or swampy conditions.
Etymology
glyceria: From the Greek glykos ‘sweet’.
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.