Description
A member of the spear grass group, Cane Needle Grass (Nassella hyalina) is a perennial tussockforming grass to 0.8 m (or sometimes 1.5 m) high. The leaves are flat or rolled slightly inwards, up to 20 cm long and 4 mm wide, strongly ribbed and with rough to touch (‘scabrous’) margins. They have a small (0.2-2 mm long) in-rolled, hairless ‘ligule’. The ligule is the small flap at the junction of the leaf blade and the leaf sheath. It can be located by tracing a leaf down to where it joins the sheath and bending the leaf back at this point.
The branching flower heads (called panicles) grow to about 25 cm long. The pointed bracts (called glumes) enclosing the flowers are translucent and straw-coloured. The seeds are 3.5-5 mm long and have a 2-4.5 cm long bristle or awn, which is twisted near the base and twice bent. The awn is surrounded by a cylindrical crown, or ‘corona’, of hard tissue to 0.5 mm (or sometimes up to 1 mm or slightly more) long from the tip of the seed body. The upper margin of the corona is divided into numerous small slender, translucent spines or hair-like projections. The short pointed base, or ‘callus’, is curved and silky hairy. Cane Needle Grass can also produce ‘stem’ seeds, or ‘cleistogenes’, hidden in the sheaths at the base of the clump.
For further information and assistance with identification of Cane Needle Grass contact the herbarium in your state or territory.
Distribution:
Major infestations of Cane Needle Grass occur around the outer northern and western suburbs of Melbourne and in central Victoria. Cane Needle Grass is uncommon in New South Wales where it has been found in the north-eastern part of the state and also reported for the Central Western Slopes, as well as several cultivated records.
Based on climatic suitability, the potential distribution of Cane Needle Grass in Australia has been estimated at 900 000 ha, with large areas of Victoria and New South Wales at risk. However, its potential to damage the natural environment is largely unknown as it has not been adequately mapped.
Habit:
Grass
Key points:
- Cane Needle Grass (Nassella hyalina) forms dense infestations which exclude other more desirable species.
- It has very sharp seeds which are easily spread by attaching to clothing, fur and machinery.
- Major infestations occur around the outer western suburbs of Melbourne and central Victoria. It has also been recorded in New South Wales.
- Prevention and early intervention are the most cost-effective forms of weed control.
How it spreads:
Cane Needle Grass spreads by seeds. Although the exact amount of seed produced is not known, both of the closely related species, Serrated Tussock (Nassella trichotoma) and Chilean Needle Grass (N. neesiana), can produce tens of thousands of seeds per plant per year.
The seeds are very sharp, and readily attach themselves to clothing, fur and equipment. Seeds can also be spread when soil is moved. Most seeds are produced in flower heads at the ends of stems; however, Cane Needle Grass has an unusual feature in that it also produces ‘stem’ seeds, which are formed at the base of the clump. These hidden seeds enable the plant to reproduce despite grazing, slashing and fire.
Cane Needle Grass also has an unusual seed dispersal mechanism. After seed drop, the second last stem node (joint) becomes fragile and can be broken by passing animals, wind and water. This disperses the hidden seeds that are contained in the above-ground sections of the stems.
Where it grows:
Cane Needle Grass is found in a variety of habitats, usually on fertile soils, including black volcanic soils and grey cracking clays on basalt near Melbourne.
Like many other Stipoid grasses, Nassella species often invade sites that are already highly degraded, especially land with higher fertility soil that has been used for grazing or farming. In addition to growing in pastures and weedy areas on grassland plains, Cane Needle Grass has invaded open woodlands and native grasslands. It has also been observed growing in areas subject to seasonal waterlogging and in riparian vegetation.
Flower colour:
Green
Distribution map:
Impacts:
Cane Needle Grass is on the Alert List for Environmental Weeds, a list of 28 non-native plants that threaten biodiversity and cause other environmental damage. Although only in the early stages of establishment, these weeds have the potential to seriously degrade Australia’s ecosystems.
Although not currently seen as a threat to agriculture, Cane Needle Grass could have a serious impact on agricultural production in the future. It is drought tolerant and forms dense, competitive infestations. It is closely related to Serrated Tussock, a Weed of National Significance, which costs south-eastern Australia’s grazing industries more than $40 million annually in control and lost production. Several species of Nassella have proved difficult to control and are now environmental and agricultural weeds.
Besides loss of production and environmental damage, the sharp seeds of Nassella species can damage sheep skins and carcasses and contaminate fleeces. While some reports describe it as palatable to stock and suitable as reasonable fodder, Cane Needle Grass is also described as quite sparse with only intermediate feed value.
Cane Needle Grass threatens a number of conservation reserves west of Melbourne. It appears to be spreading, especially in wetter areas within open native grasslands. It has the potential to affect the biodiversity of riverbank vegetation and grassland, especially in areas that remain wet for long periods.
Origin:
Cane Needle Grass is native to Argentina, southern Brazil and Uruguay.
