Scientific Name

Nassella charruana (Arechav.) Barkworth

Synonyms

Stipa charruana Arechav.

Common Names

lobed needle grass, lobed needlegrass, Uruguayan needlegrass

Family

Gramineae (South Australia)
Poaceae (Queensland, New South Wales, the ACT, Victoria, Tasmania, Western Australia and the Northern Territory)

Origin

Native to southern South America (i.e. southern Brazil, Argentina and Uruguay).

Naturalised Distribution

Locally naturalised in southern Victoria.

Habitat

A potential weed of temperate and semi-arid regions that inhabits pastures, grasslands, grassy open woodlands, roadsides, waste areas and disturbed sites.

Distinguishing Features

• a long-lived tufted grass with upright stems growing 25-100 cm tall.
  
  
• its linear leaves (0.5-2 mm wide) may be either flat or rolled inwards.
  
  
• its seed-head is usually an open panicle (6-30 cm long) with many flower spikelets that are borne singly.
  
  
• these flower spikelets are elongated in shape (16-20 mm long) and topped by a large twisted awn (45-80 mm long).
  
  
• mature seeds have a distinctive membranous structure (about 5-6 mm long) where the awn attaches to the top of the seed.

Habit

A long-lived (i.e. perennial) tufted grass with upright (i.e. erect) stems growing 25-100 cm tall. It forms dense tufts via very short creeping underground stems (i.e. rhizomes).

Stems and Leaves

The flowering stems (i.e. culms) are upright (i.e. erect) and most of the leaves are tufted around the base of the plant.

The leaves are long and narrow (i.e. linear) and have a hairless (i.e. glabrous) sheath which surrounds the stem. The leaf blades (5-20 cm long and only 0.5-2 mm wide) are flat or rolled inwards (i.e. convolute) and have pointed tips (i.e. acuminate apices). Where the leaf sheath meets the leaf blade there is a small membranous structure (i.e. eciliate ligule) 0.8-2 mm long.

Flowers and Fruit

The seed-head (6-30 cm long) is an open, or sometimes spike-like (i.e. spiciform), panicle. Small flower spikelets are borne singly at the tips of the branches of the seed-heads, and each flower spikelet consists of two bracts (i.e. glumes) and a single tiny flower (i.e. floret). These flower spikelets (16-20 mm long) are elongated or cylindrical (i.e. lanceolate or terete) in shape and are topped by a very long awn.

When mature the 'seed' separates from the bracts (i.e. glumes), which remain on the seed-head branches. The mature 'seed' has a sharpened, hairy tip (i.e. pubescent callus) at one end and a long twisted awn (45-80 mm long) at the other end. Where the awn attaches to the 'seed' there is a distinctive membranous collar-like structure (i.e. corona) about 5-6 mm long. Hidden within the hard-coated 'seed' is the long and narrow (i.e. linear) and dark brown-coloured grain (about 3.5 mm long).

Reproduction and Dispersal

This species reproduces via seed. These seeds readily attach to animals, clothing and vehicles. They may also be dispersed in contaminated agricultural produce (e.g. fodder) and soil.

Impacts

Lobed needlegrass (Nassella charruana) is on the Alert List for Environmental Weeds, a list of 28 introduced plants that are currently not very widespread but are considered to pose a threat to Australia's environment.

Similar Species

Lobed needlegrass (Nassella charruana) is very similar similar to Chilean needlegrass (Nassella neesiana ), cane needlegrass (Nassella hyalina ), Texas needlegrass (Nassella leucotricha ) and short-spined needlegrass (Nassella megapotamia). These species can be distinguished by the following differences:

• lobed needlegrass (Nassella charruana) has seeds with relatively long awns (more than 45 mm long) and a long corona (5-6 mm long). Its flower spikelets are relatively large (16-20 mm long) and it does not produce stem seeds (i.e. cleistogenes).
  
  
• Chilean needlegrass (Nassella neesiana ) has seeds with relatively long awns (more than 45 mm long) and a short corona (less than 1.5 mm long). Its flower spikelets are relatively large (10-22 mm long) and it produces stem seeds (i.e. cleistogenes).
  
  
• cane needlegrass (Nassella hyalina ) has seeds with relatively short awns (20-45 mm long) and a short corona (less than 1.5 mm long). Its flower spikelets are relatively small (5-12 mm long) and it produces stem seeds (i.e. cleistogenes).
  
  
• Texas needlegrass (Nassella leucotricha ) has seeds with relatively long awns (more than 45 mm long) and a moderately-sized corona (1.5-2.5 mm long). Its flower spikelets are relatively large (10-17 mm long) and it produces stem seeds (i.e. cleistogenes).
  
  
• short-spined needlegrass (Nassella megapotamia) has seeds with relatively long awns (more than 45 mm long) and a short corona (less than 1.5 mm long). Its flower spikelets are relatively small (7-10 mm long) and it does not produce stem seeds (i.e. cleistogenes).

Several other introduced grasses are relatively similar. These include serrated tussock (Nassella trichotoma ), Mexican feathergrass (Nassella tenuissima ), broad kernel espartillo (Amelichloa caudata ), narrow kernel espartillo (Amelichloa brachychaeta), plumerillo (Jarava plumosa ) and Uruguayan ricegrass (Piptochaetium montevidense ). None of these species have collars (i.e. coronas) on their seeds.

In addition, several native tussock -forming grasses can look similar (e.g. Poa spp. and Austrostipa spp.). However, these species either lack ligules on their leaves, or have ligules that are fringed with hairs, and they also do not have collars (i.e. coronas) on their seeds.

Note: This page only covers those grasses that are commonly confused with this species. For a more in-depth key to all of the grasses present in Australia, see the AusGrass: Grasses of Australia CD-ROM or Flora of Australia, Volumes 43 and 44.

Legislation

This species is declared under legislation in the following states and territories:

• ACT: C1 - notifiable pest plant (a pest plant whose presence must be notified), and C4 - prohibited pest plant (a pest plant whose propagation and supply is prohibited).
  
  
• Victoria: S - prohibited and is to be eradicated from the state if possible.
  
  
• Western Australia: Unassessed - this species is declared in other states or territories and is prohibited until assessed via a weed risk assessment (throughout the entire state).
   
  

Management

For information on the management of this species see the following resources:

• the Victorian Department of Primary Industries Landcare Note on this species, which is available online at http://www.dpi.vic.gov.au.

Sources

Anonymous (1999). Lobed needle grass. Landcare Notes. Keith Turnbull Research Institute, Natural Resources and Environment, Frankston, Victoria.

Anonymous (2002). A Global Compendium of Weeds. http://www.hear.org/gcw. Hawaiian Ecosystems at Risk Project and Department of Agriculture - Western Australia.

Anonymous (2002). Australia's Virtual Herbarium. http://www.anbg.gov.au/avh. Australian National Botanic Gardens, Environment Australia, Canberra, ACT.

Anonymous (2003). Under Control. Pest Plant and Animal Management News. Number 24. State of Victoria, Department of Primary Industries.

Anonymous (2006). Germplasm Resources Information Network (GRIN). http://www.ars-grin.gov/cgi-bin/npgs/html/index.pl. National Germplasm Resources Laboratory, National Genetic Resources Program, Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Beltsville, Maryland, USA.

Anonymous (2007). Weeds Australia. http://www.weeds.org.au. National Weeds Strategy Executive Committee, Launceston, Tasmania.

Muyt, A. (2001). Bush Invaders of South-East Australia. R.G. and F.J. Richardson, Meredith, Victoria.

Navie, S.C. (2004). Declared Plants of Australia. CD-ROM. The University of Queensland, St. Lucia, Queensland.

Sharp, D. and Simon, B. (2002). Ausgrass: an interactive key to Australian grasses. CD-ROM. Queensland Herbarium, Brisbane, Queensland.