Quick Facts

Quick facts

  • Narrow Kernel Espartillo (Amelichloa brachychaeta) is a tussock forming grass species that occurs as a weed of roadsides, grasslands, stream banks and disturbed site.
  • It is not currently widespread in Australia, but is known to be problematic in Argentina and California where it is a weed of lucerne.
  • Seed can be spread by stock or humans as they readily stick to wool, fur and clothing.
  • Some flower heads are produced within the upper and lower leaf sheaths where self-pollination and seed production can occur.

What Does It Look Like?

What is it?

Narrow Kernel Espartillo (Amelichloa brachychaeta) is a perennial (long lived) tussock forming grass with upright stems growing 40–100 cm tall. The leaf sheaths are hairless on the surface, with hairy outer margins. A small membranous structure (ligule) is present at the base of each leaf blade, which is 0.1–0.5 mm long, and has an abruptly flattened (truncate) or obtuse tip, with tufted hairs on each side. The leaf blades are 8–35 cm long, 0.5–3 mm wide, thread-like (filiform), and can be inwardly rolled (involute), flattened, or outwardly rolled (convolute). The leaf blade surface is rough and hairless, and its margins are lined with small hairs (ciliate) and hairy at the base (Sharp & Simon 2002).

Narrow Kernel Espartillo has two types of seed-head. The more obvious seed-heads are elongated clusters (panicles) found towards the top of the plant, that are 10–25 cm long, and consist of widely spaced few-flowered branches. The solitary spikelets are 6–8 mm long, and each produces a solitary seed with a hairy base and a long, twisted bristle-like structure (awn) 12–18 mm long. The florets are cylindrical, 4–5.5 mm long. At maturity, the spikelets break up, leaving the glumes (outer spikelet bracts, or modified leaves) attached to the flower stem. A second type of inflorescence is produced within the leaf sheaths, and this consists of widely spaced greenish spikelets. The flowers within these flower-heads are self-pollinated.

The seeds are yellow-brown and somewhat rounded or oblong, 2–3 mm long and 0.9–1 mm wide, with a hairy seed coat. The self-pollinated seeds (cleistogenes) occur in both the upper and lower sheaths (Parsons & Cuthbertson 2001; Sharp & Simon 2002; Navie 2004).

For further information and assistance with identification of Narrow Kernel Espartillo, contact the herbarium in your state or territory.

Flower colour

Brown, Green

Growth form (weed type/habit)


Where it currently grows? Preferred habitat

Narrow Kernel Espartillo occurs in temperate grasslands in the Southern Hemisphere and occurs as a weed of roadsides, grasslands, stream banks, disturbed sites, waste areas and disused pastures (Parsons & Cuthbertson 2001).

Are there similar species?

Narrow Kernel Espartillo can be difficult to distinguish from Broad Kernel Espartillo (Amelichloa caudata) [as Achnatherum caudatum], with the only distinguishing features being minor differences in floral structure (Parsons & Cuthbertson 2001). Broad Kernel Espartillo has broader grains, 1–1.4 mm wide, with partially hairy seed coats (lemma). In contrast, Narrow Kernel Espartillo has narrower grains, 0.9–1 mm wide, with more densely hairy seed coats. The self-pollinated seeds (i.e., those produced within the leaf sheaths) in Broad Kernel Espartillo are produced only in the lower leaf sheaths, while those of Narrow Kernel Espartillo are produced in both upper and lower sheaths (Navie 2004).

Narrow Kernel Espartillo is also similar to several native Speargrasses (Austrostipa spp.), but can be distinguished from these species by its membranous ligules. It is also similar to a number of introduced species including Needlegrasses (Nassella spp.), Uruguayan Ricegrass (Piptochaetium montevidense) and Plumerillo (Jarava plumosa). It can be distinguished from Mexican Feathergrass (Nassella tenuissima) and Serrated Tussock (Nassella trichotoma) by its generally broader leaves (1–7 mm wide, compared to 1 mm wide) and it can be distinguished from the Needlegrasses (Nassella spp.) as its seeds do not have a crown-like structure (corona) where the awn meets the seed. Narrow Kernel Espartillo can be distinguished from Uruguayan Ricegrass by its elongated grain and from Plumerillo by the lack of a plume of hairs on the lower part of the awn (Navie 2004).

Why Is It A Weed?

What are its impacts?

Agriculture: In its native range in Argentina and in California, Narrow Kernel Espartillo is a serious problem in lucerne pastures (Encycloweedia 2008) where it reduces yield and interferes with mowing. Although palatable when young, the adult plants are highly unpalatable to most stock and are not readily grazed (Parsons & Cuthbertson 2001).

How does it spread?

Narrow Kernel Espartillo is solely seed dispersed. The seeds can be dispersed by stock, wildlife and humans as they readily stick to wool, fur and clothing. Seeds can also be dispersed by farm or other machinery, in mud stuck to shoes or hooves and by flowing water (Parsons & Cuthbertson 2001).

What is its history in Australia?

The precise time of introduction of Narrow Kernel Espartillo into Australia is not known. This species was first recorded near Merriwa in New South Wales in 1955 and has since spread (Parsons & Cuthbertson 2001).

How To Manage It?

Best practice management

Non-chemical control: Winter cropping and repeated cultivation are effective in controlling Narrow Kernel Espartillo, but when this species invades pastures, control is more difficult. Light stock grazing and rotational or strip grazing should maintain pasture competitiveness and slow the invasion of the weed. Reports from Argentina suggest that mixed pastures of lucerne, white clover, cocksfoot and prairie grass are useful for control because cattle seem to prefer to graze the other species over the lucerne, enabling the lucerne to suppress the weed (Parsons & Cuthbertson 2001; Encycloweedia 2008).

Narrow Kernel Espartillo does not reproduce vegetatively, so the removal of flowers before setting seed can be effective. However, this species can produce seed within the leaf sheaths without cross fertilisation (this is called cleistogamy). After mowing, vegetative growth can be rapid, and cleistogamous seeds can be produced without the presence of the more obvious flower-heads, allowing the infestation to persist. Clumps of this weed should be removed, dried and possibly burned (Encycloweedia 2008).

Chemical control: Herbicides can be useful in controlling this species. In invaded pastures, grazing can be used to reduce the height of the preferred species, followed by direct application or spot spraying of herbicide to the weed (Parsons & Cuthbertson 2001). Crop rotation that allows tillage and the use of selective herbicides is also effective in controlling this species, but sites should be monitored for regrowth and new seedling recruitment after treatment (Encycloweedia 2008).

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au

Does it have a biological control agent?


When does it grow? (lifecycle/growth calendar)

Narrow Kernel Espartillo is a long lived (perennial) species. The seeds germinate in autumn, with slow seedling growth throughout winter. The flowering stems (culms) develop in spring and flowering occurs in late spring or early summer, continuing throughout summer depending on water availability. Growth slows or ceases in winter and new tillers (daughter shoots that sprout from the parent plant) develop the following spring (Parsons & Cuthbertson 2001).

Where Is It Found?

Which states and territories is it found?


What areas within states and territories is it found?

Narrow Kernel Espartillo is not widely naturalised in Australia and is only known to occur in the North-Western and Central-Western Slope regions of New South Wales (Sharp & Simon 2002).

Where does it originate?

Narrow Kernel Espartillo is native to South America (Parsons & Cuthbertson 2001).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?


Where is it a declared weed?


Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?


Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?


Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Amelichloa brachychaeta

Other scientific names (synonyms)?

  • Achnatherum brachychaetum (Godr.) Barkworth
  • Jarava brachychaeta (Godr.) Penail.
  • Stipa brachychaeta Godr.

Does it have other known common name(s)?


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