Job’s Tears

WEEDS AUSTRALIA - profiles

Cyperus esculentus L. by State of Queensland(©State of Queensland)

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Quick Facts

Quick facts

  • Job's Tears (Coix aquatica) is a perennial aquatic grass.
  • Its seeds are enclosed in a bony, bead-like structure.
  • It is a deep-water species that grows in lakes, streams, marshy borders and open water.
  • It is not currently naturalised in Australia.

What Does It Look Like?

What is it?

Job's Tears (Coix aquatica) is a perennial aquatic grass. The stems are spongy and creeping and produce roots at the base. Plants are sometimes floating and the stems can reach up to 30 m long and about 1 cm in diameter. The flowering stems are up to 2 m tall. The leaf sheaths (part of the leaves that clasp the stems) are smooth and hairless, or slightly rough. The leaf blades are up to 100 cm long and 0.3–2.5 cm wide, rounded at the base and hairy on both surfaces. The mid vein is stout and the leaf margins are rough to the touch.

Separate male and female flowers occur on the same plant. The female inflorescence (flowering structure) is completely enclosed in a modified leaf sheath that forms a bony, bead-like structure. The male flowers arise from the tip of the female inflorescence in a strongly drooping cluster.

The fruit is hard, shiny and egg-shaped, 10–14 mm long and 5–7 mm wide, white or pale brown, sometimes with a line running up the middle. The tip is occasionally extended into a green blade (Waterhouse & Mitchell 1998; Chen & Phillips 2006; Clayton et al. 2006).

For further information and assistance with identification of Job's Tears, contact the herbarium in your state or territory.

Flower colour

Unknown

Growth form (weed type/habit)

Grass

Where it currently grows? Preferred habitat

Job's Tears is a deep-water grass, and prefers lakes, streams, marshy borders and open water (Chen & Phillips 2006).

Are there similar species?

Job's Tears is one of approximately 25 species of Coix, three of which occur in Australia (Sharp & Simon 2002).

The closely related Australian species, Coix lacryma-jobi, has smaller male flowers, in clusters that are only slightly drooping (strongly drooping in Job's Tears) (Waterhouse & Mitchell 1998).

Why Is It A Weed?

What are its impacts?

Agriculture: Job's Tears is an agricultural weed, cultivation escape, and an environmental weed. It is a serious weed of waterways in Thailand (Waterhouse & Mitchell 1998).

How does it spread?

Job's Tears is dispersed by seed and stem fragments (PIER 2008).

What is its history in Australia?

Job's Tears is not currently naturalised in Australia.

How To Manage It?

Best practice management

Prevention: There is no information available on the control of Job's Tears. As the species is presently not found in Australia, the most effective form of control is prevention.

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Job's Tears is a tropical perennial grass (PIER 2008). It flowers and fruits from August to November in China (Chen & Phillips 2006).

Where Is It Found?

Which states and territories is it found?

Not naturalised in any Australian states or territories.

What areas within states and territories is it found?

Job's Tears is not currently naturalised in Australia.

Where does it originate?

Job's Tears is native to temperate and tropical Asia and is found in China, India, Cambodia, Laos, Myanmar, Thailand and Vietnam (GRIN 2008).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NT

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

Coix aquatica

Other scientific names (synonyms)?

 

Bibliography

Australian Plant Census (2011) available at http://www.anbg.gov.au/cgi-bin/apclist.

Chen, S.-l., and Phillips, S. M. (2006). Coix aquatica. Flora of China. http://efloras.org/florataxon.aspx?flora_id=2&taxon_id=200025078 

Clayton, W.D., Harman, K.T. and Williamson, H. (2006–). GrassBase – The Online World Grass Flora. Available at http://www.kew.org/data/grasses-db/www/imp02497.htm 

GRIN (2008). USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. Available at http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?400777 

Han Y-H., Li D-Y., Li Y-C., Xue Y-G., Hu Z-L., Song Y-C. (2004). Cytogenetic identification of a new hexaploid Coix aquatica cyto-type. Journal of Integrative Plant Biology 46(6): 724–729.

Pacific Island Ecosystems at Risk (PIER) (2008). Coix lacryma-jobi. Institute of Pacific Islands Forestry, US Forest Service. Available at http://www.hear.org/pier/species/coix_lacryma-jobi.htm 

Sharp, D. and Simon, B.K. (2002). AusGrass: Grasses of Australia. ABRS, Canberra.

Waterhouse, B.M. and Mitchell, A.A. (1998). Northern Australia Quarantine Strategy: Weeds Target List, Second Edition. Australian Quarantine & Inspection Service, Miscellaneous Publication No. 6/98.

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