Quick Facts

Quick facts

• Broad Kernel Espartillo (Amelichloa caudata) is a long lived tussock forming grass native to South America.
• It is a weed of native grasslands, open forests, grazing land and disturbed sites.
• In its native range it can be a serious weed of lucerne.
• It can produce seeds without cross pollination from self fertilising flowers borne within the lower leaf sheaths.

What Does It Look Like?

What is it?

Broad Kernel Espartillo (Amelichloa caudata) is a long lived (perennial) tussock forming grass with upright stems that are 55-100 cm tall. The leaf sheaths are hairless on the surface, with hairy outer leaf margins. A small membranous structure (ligule) is present at the base of each leaf blade, is 01-0.5 mm long and has an abruptly flattened (truncate) or obtuse (with an angle between 90 and 180 degrees) tip, with tufted hairs on each side. The leaf blades are 25-70 cm long, 1-7 mm wide, straight or slightly curved, linear or thread-like (filiform) and can be inwardly rolled (involute), flattened, or outwardly rolled (convolute). The leaf blade surface is slightly rough (scaberelous, or minutely scabrous), hairless and its margins are lined with small hairs (cilia) (Sharp & Simon 2002; Navie 2004).

Broad Kernel Espartillo has two types of seed-head. The more obvious seed heads are elongated clusters (panicles) found towards the top of the plant, 15-25 cm long, 2-3 cm wide and consist of widely spaced few-flowered branches. The solitary spikelets (partial inflorescence or floral structure) are 5-11 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, 4-6 mm long and densely covered with short white hairs. 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 (called a cleistogene) is produced within the leaf sheaths at the base of the plant and consists of widely spaced greenish spikelets, that are 8-12 mm long. The flowers within these flower-heads are self-pollinated and do not open. The seeds are yellow-brown and somewhat rounded, 2-3 mm long and 1-1.4 mm wide, with a partially hairy seed coat (Parsons & Cuthbertson 2001; Sharp & Simon 2002; Navie 2004).

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

Flower colour

Brown, Green

Growth form (weed type/habit)

Grass

Where it currently grows? Preferred habitat

Broad Kernel Espartillo is a weed of native grasslands, open forests, grazing land, disturbed sites and waterways (Navie 2004).

Are there similar species?

Broad Kernel Espartillo can be difficult to distinguish from Narrow Kernel Espartillo (Amelichloa brachychaeta) [as Achnatherum brachychaetum], 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 (pubescent). 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).

Broad 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). It differs from the Needlegrasses (Nassella spp.) in not having a membranous crown-like structure (corona) where the awn meets the seed. It 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?

In its native Argentina and in California, Broad 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?

Broad Kernel Espartillo is solely seed dispersed. The seeds can be dispersed by stock, wildlife and humans as the awns of the seeds readily attaching 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 Broad Kernel Espartillo into Australia is not known. It was first recorded in 1959 near Cootamundra, New South Wales. It has since spread into several areas in New South Wales and Victoria, where it is spreading rapidly and is of particular concern (Parsons & Cuthbertson 2001).

How To Manage It?

Best practice management

Winter cropping and repeated cultivation are effective in controlling Broad 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 in controlling Broad Kernel Espartillo because cattle seem to prefer the graze the other species over the lucerne, enabling the lucerne to suppress the weed (Parsons & Cuthbertson 2001; Encycloweedia 2008).

Broad 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 (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).

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?

NO

When does it grow? (lifecycle/growth calendar)

Broad 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, with new tillers (daughter shoots that sprout from the parent plant) developing the following spring (Parsons & Cuthbertson 2001).

Where Is It Found?

Which states and territories is it found?

NSW, TAS, VIC

What areas within states and territories is it found?

Broad Kernel Espartillo occurs in the North-Western, Central-Western and South-Western Slopes and South-Western Plains in New South Wales, and in the Midlands in Victoria (Sharp & Simon 2002). In Tasmania, the distribution of Broad Kernel Espartillo is relatively limited, with it occurring in localised populations on Flinders Island and other islands in Bass Strait (Tasmanian Department of Primary Industries and Water 2008).

Where does it originate?

Broad Kernel Espartillo is native to South America, but has spread into Australia, Africa and North America (Parsons & Cuthbertson 2001).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

ACT, SA, TAS, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Amelichloa caudata

Other scientific names (synonyms)?

• Achnatherum caudatum (Trin.) S.W.L. Jacobs & J. Everett
• Jarava caudata (Trin.) Penail.
• Stipa caudata Trin.

Does it have other known common name(s)?

Espartillo, Speargrass, Chilean Ricegrass, Puna Grass