Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Heteropogon contortus
(spear grass)

Dube S, 2017. Heteropogon contortus (spear grass). Invasive Species Compendium. Wallingford, UK: CABI. DOI:10.1079/ISC.26983.20203483213

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Datasheet

Heteropogon contortus (spear grass)

Summary

  • Last modified
  • 24 September 2020
  • Datasheet Type(s)
  • Invasive Species
  • Pest
  • Host Plant
  • Preferred Scientific Name
  • Heteropogon contortus
  • Preferred Common Name
  • spear grass
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Monocotyledonae
  • Summary of Invasiveness
  • Heteropogon contortus is a perennial, short-lived, tufted grass native to Africa, temperate and tropical Asia, Australasia and southwestern Europe (U...

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Pictures

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PictureTitleCaptionCopyright
Heteropogon contortus (black speargrass); roadside habit. Perennial, tufted, short-lived grass (2-5 years) up to 1.5 m in height, but often less than 1 m. Australia. April 2011.
TitleHabit
CaptionHeteropogon contortus (black speargrass); roadside habit. Perennial, tufted, short-lived grass (2-5 years) up to 1.5 m in height, but often less than 1 m. Australia. April 2011.
Copyright©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); roadside habit. Perennial, tufted, short-lived grass (2-5 years) up to 1.5 m in height, but often less than 1 m. Australia. April 2011.
HabitHeteropogon contortus (black speargrass); roadside habit. Perennial, tufted, short-lived grass (2-5 years) up to 1.5 m in height, but often less than 1 m. Australia. April 2011.©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); roadside habit. Perennial, tufted, short-lived grass (2-5 years) up to 1.5 m in height, but usually less than 1 m. Australia. April 2006.
TitleHabit
CaptionHeteropogon contortus (black speargrass); roadside habit. Perennial, tufted, short-lived grass (2-5 years) up to 1.5 m in height, but usually less than 1 m. Australia. April 2006.
Copyright©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); roadside habit. Perennial, tufted, short-lived grass (2-5 years) up to 1.5 m in height, but usually less than 1 m. Australia. April 2006.
HabitHeteropogon contortus (black speargrass); roadside habit. Perennial, tufted, short-lived grass (2-5 years) up to 1.5 m in height, but usually less than 1 m. Australia. April 2006.©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); habit. Australia. April 2006.
TitleHabit
CaptionHeteropogon contortus (black speargrass); habit. Australia. April 2006.
Copyright©Harry Rose/Macleay Grass Man/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); habit. Australia. April 2006.
HabitHeteropogon contortus (black speargrass); habit. Australia. April 2006.©Harry Rose/Macleay Grass Man/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); spikelets. Spikelets paired. Lower pairs are alike in sex and shape, and either male or sterile. Upper pairs are dissimilar, 1 sessile, fertile and awned, the other pedicellate, male or sterile and awnless. Florets 2, the lower sterile and the upper female or bisexual in the fertile spikelets. Both florets are male or sterile in all the other spikelets. Upper lemma of the fertile spikelet is stipe-like, passing into a bent awn. Australia. April 2006.
TitleSpikelets
CaptionHeteropogon contortus (black speargrass); spikelets. Spikelets paired. Lower pairs are alike in sex and shape, and either male or sterile. Upper pairs are dissimilar, 1 sessile, fertile and awned, the other pedicellate, male or sterile and awnless. Florets 2, the lower sterile and the upper female or bisexual in the fertile spikelets. Both florets are male or sterile in all the other spikelets. Upper lemma of the fertile spikelet is stipe-like, passing into a bent awn. Australia. April 2006.
Copyright©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); spikelets. Spikelets paired. Lower pairs are alike in sex and shape, and either male or sterile. Upper pairs are dissimilar, 1 sessile, fertile and awned, the other pedicellate, male or sterile and awnless. Florets 2, the lower sterile and the upper female or bisexual in the fertile spikelets. Both florets are male or sterile in all the other spikelets. Upper lemma of the fertile spikelet is stipe-like, passing into a bent awn. Australia. April 2006.
SpikeletsHeteropogon contortus (black speargrass); spikelets. Spikelets paired. Lower pairs are alike in sex and shape, and either male or sterile. Upper pairs are dissimilar, 1 sessile, fertile and awned, the other pedicellate, male or sterile and awnless. Florets 2, the lower sterile and the upper female or bisexual in the fertile spikelets. Both florets are male or sterile in all the other spikelets. Upper lemma of the fertile spikelet is stipe-like, passing into a bent awn. Australia. April 2006.©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); ligule. Ligules are membranous, with a fringe of hairs. Leaves are bluish-green, with hairs near their base. Australia. January 2005.
TitleLigule
CaptionHeteropogon contortus (black speargrass); ligule. Ligules are membranous, with a fringe of hairs. Leaves are bluish-green, with hairs near their base. Australia. January 2005.
Copyright©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); ligule. Ligules are membranous, with a fringe of hairs. Leaves are bluish-green, with hairs near their base. Australia. January 2005.
LiguleHeteropogon contortus (black speargrass); ligule. Ligules are membranous, with a fringe of hairs. Leaves are bluish-green, with hairs near their base. Australia. January 2005.©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); sheath.  Leaves are bluish-green with hairs near their base. Ligules are membranous with a fringe of hairs. Australia. January 2005.
TitleSheath
CaptionHeteropogon contortus (black speargrass); sheath. Leaves are bluish-green with hairs near their base. Ligules are membranous with a fringe of hairs. Australia. January 2005.
Copyright©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); sheath.  Leaves are bluish-green with hairs near their base. Ligules are membranous with a fringe of hairs. Australia. January 2005.
SheathHeteropogon contortus (black speargrass); sheath. Leaves are bluish-green with hairs near their base. Ligules are membranous with a fringe of hairs. Australia. January 2005.©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); habit. Charles Darwin National Park, Darwin Northern Territories, Australia. November 2010.
TitleHabit
CaptionHeteropogon contortus (black speargrass); habit. Charles Darwin National Park, Darwin Northern Territories, Australia. November 2010.
Copyright©John Tann/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); habit. Charles Darwin National Park, Darwin Northern Territories, Australia. November 2010.
HabitHeteropogon contortus (black speargrass); habit. Charles Darwin National Park, Darwin Northern Territories, Australia. November 2010.©John Tann/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); flowering habit. Rangareddy district, Andhra Pradesh, India. November 2009.
TitleFlowering habit
CaptionHeteropogon contortus (black speargrass); flowering habit. Rangareddy district, Andhra Pradesh, India. November 2009.
Copyright©J.M. Garg/via wikipedia - CC BY 3.0
Heteropogon contortus (black speargrass); flowering habit. Rangareddy district, Andhra Pradesh, India. November 2009.
Flowering habitHeteropogon contortus (black speargrass); flowering habit. Rangareddy district, Andhra Pradesh, India. November 2009.©J.M. Garg/via wikipedia - CC BY 3.0
Heteropogon contortus (black speargrass); flowerhead. Flowerheads are spatheate, with hairy racemes., and each raceme is ca.4-6 cm long, has long intertwined, black-brown awns arising from a number of paired spikelets (1 unstalked and awned, the other stalked and unawned).
TitleFlowerheads
CaptionHeteropogon contortus (black speargrass); flowerhead. Flowerheads are spatheate, with hairy racemes., and each raceme is ca.4-6 cm long, has long intertwined, black-brown awns arising from a number of paired spikelets (1 unstalked and awned, the other stalked and unawned).
Copyright©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); flowerhead. Flowerheads are spatheate, with hairy racemes., and each raceme is ca.4-6 cm long, has long intertwined, black-brown awns arising from a number of paired spikelets (1 unstalked and awned, the other stalked and unawned).
FlowerheadsHeteropogon contortus (black speargrass); flowerhead. Flowerheads are spatheate, with hairy racemes., and each raceme is ca.4-6 cm long, has long intertwined, black-brown awns arising from a number of paired spikelets (1 unstalked and awned, the other stalked and unawned).©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); seeds, in hand. USDA Plant Materials Center, Molokai, Hawaii, USA July 2012.
TitleSeeds
CaptionHeteropogon contortus (black speargrass); seeds, in hand. USDA Plant Materials Center, Molokai, Hawaii, USA July 2012.
Copyright©Forest & Kim Starr - CC BY 4.0
Heteropogon contortus (black speargrass); seeds, in hand. USDA Plant Materials Center, Molokai, Hawaii, USA July 2012.
SeedsHeteropogon contortus (black speargrass); seeds, in hand. USDA Plant Materials Center, Molokai, Hawaii, USA July 2012.©Forest & Kim Starr - CC BY 4.0
Heteropogon contortus (black speargrass); habit, showing contorted form at maturity. Australia. July 2005.
TitleHabit
CaptionHeteropogon contortus (black speargrass); habit, showing contorted form at maturity. Australia. July 2005.
Copyright©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); habit, showing contorted form at maturity. Australia. July 2005.
HabitHeteropogon contortus (black speargrass); habit, showing contorted form at maturity. Australia. July 2005.©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); habit. Australia. January 2006.
TitleHabit
CaptionHeteropogon contortus (black speargrass); habit. Australia. January 2006.
Copyright©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0
Heteropogon contortus (black speargrass); habit. Australia. January 2006.
HabitHeteropogon contortus (black speargrass); habit. Australia. January 2006.©Harry Rose (Macleay Grass Man)/via flickr - CC BY 2.0

Identity

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Preferred Scientific Name

  • Heteropogon contortus (L.) P. Beauv. ex Roem. & Schult.

Preferred Common Name

  • spear grass

Other Scientific Names

  • Andropogon allionii DC.
  • Andropogon besukiensis Steud.
  • Andropogon contortus L.
  • Andropogon firmus (J. Presl) Kunth
  • Andropogon hispidissimus Hochst. ex Steud.
  • Heteropogon allionii (DC.) Roem. & Schult.
  • Heteropogon besukiensis (Steud.) Miq.
  • Heteropogon fertilis B.S. Sun & S. Wang
  • Heteropogon firmus J. Presl
  • Heteropogon hirsutus P. Beauv.
  • Heteropogon roxburghii Nees
  • Holcus contortus (L.) Kuntze ex Stuck.
  • Sorghum contortum (L.) Kuntze

International Common Names

  • English: assegai fix; assegai grass; bellary grass; black spear grass; black speargrass; bunch spear grass; bunch speargrass; common spear grass; kusal grass; piercing grass; pili grass; spider's arrows; stick grass; tangle grass; tanglehead; tanglehead grass; twisted beardgrass; wild oats
  • Spanish: barba negra; hierba torcida; zacate acestilla; zacate barba negra; zacate retorcido; zacate retorcido moreno
  • French: herbe à moutons ; herbe barbue; herbe polisson ; heteropogon contourne
  • Chinese: huang mao; ti chin; tic chen; tien chen; tu chin
  • Portuguese: flechinha; flechinha
  • German: Speergras

Local Common Names

  • Benin: ahira
  • Burkina Faso: bubongnona sando; celbi; komango; selbo
  • Germany: Gedrehtes Bartgras
  • Ghana: ananugai; chiga
  • India: aeddi; bandapuncha; barweza; butoo jara; dabhjuliyum; dauria; eddi gaddi; ganjali hullu; gantegawta; gundha goorana; hukara gadi; hurwal; kaarda hullu; kala lapa; kantegawta; kari vunugada hullu; kari-unugada hullu; kaseri gaddi; khar; kher; kumeria; kuneria; kunura; kurunsi pullu; kusal; kusali; kusli; lamb; lamp; lampa; lap; musel; nani sukhali; nanju hullu; oobina hullu; oosi pul; oosi pullu; pandi bella gaddi; pani pullu; panree pullu; paraura; parba; parbi; pareba; parva; parwa; parwaya; pochati; ponia jara; riskawa; saga; saga jara; sarala; sarari; sariala; sarmal; sarol; sarwala; sarwar; sauri ghas; shora; shurighas; shurval; shurwal; sinkola; sona jara; sookal; sukhli kursali; sukli; sunkari hullu; sunkhali; sura; surari; suriala; survalu; surwar; surwara; suryala; tambat; yeddi; yeddi gaddi
  • Indonesia: benjeng-benjeng; marakan
  • Kenya: kichoma mguu; kichoma nguo; kishona; kishona nguo
  • Madagascar: boka; boka ahidambo
  • Mali: fila ntaso; fulanu ntaso; guenemé; moloko; niaderé
  • Mexico: aceitilla; barba negra; cabeza enmarañada; guixi biia; quixi pija; retorcido moreno; tola; zacate aceitillo; zacate colorado
  • Niger: bat sirey; bata-kirey; bat-cirey; mano-selseldé; séoko; uraba; zongwa
  • Nigeria: bara babba tudu; bunsurun daji; buzun kura; eru bere; eru buru; jan gargan; kambarahi; silka; sin; tsigà; tsigàà; tsiikaà; yartudu
  • Philippines: sibat-sibatan
  • Senegal: fila ntaso
  • South Africa: assegaaigras; gemeines; gewone pylgras; isitupe; makurwane; malgras; pieringgras; pylgras; seloka ; selokana; steekgras ; swartangel
  • Sri Lanka: itana
  • Tanzania: mahwa kinyaturu; ngonga kinyaturu
  • Thailand: lem; ya laem; ya nuat ruesi; ya rang tak kataen; yaa luuk nong; yaa phung chuu; yaa rang takka taen
  • USA/Hawaii: lule; pili
  • Zimbabwe: inzala

EPPO code

  • HTOCO

Summary of Invasiveness

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Heteropogon contortus is a perennial, short-lived, tufted grass native to Africa, temperate and tropical Asia, Australasia and southwestern Europe (USDA-ARS, 2017). It is naturalized in southern USA, Mexico, the Caribbean, Central and South America (USDA-ARS, 2017). It is rarely cultivated but spreads naturally wherever grasslands suffer from seasonal firesIt has been declared as a weed in parts of America, East Asia and in New Caledonia (Heuzé et al., 2017). It is reported as invasive in New Caledonia (ISSG, 2017) and in Cuba (Oviedo Prieto et al., 2012). In New Caledonia, it is highly invasive on sedimentary rocks and transforms invaded areas into savannahs. 

H. contortus is a valuable pasture grass, but the harpoon-like attachments on the seeds can become embedded in the wool and skin of sheep, decreasing the quality of the wool and killing the animals.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Monocotyledonae
  •                     Order: Cyperales
  •                         Family: Poaceae
  •                             Genus: Heteropogon
  •                                 Species: Heteropogon contortus

Notes on Taxonomy and Nomenclature

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Heteropogon is a genus of annual and perennial plants in the Poaceae generally known as tangleheads. The generic name Heteropogon is derived from the Greek heteros, meaning different, and pogon, meaning beard, which refers to the two kinds of spikelets present in the inflorescence of these plants. The Latin specific epithet contortus refers to the seeds, which contort when wet in order to drill into the soil (University of Hawaii, 2009). The genus Heteropogon has six species (World Flora Online, 2020) distributed in tropical and sub-tropical regions of the world.

Description

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This description is from Flora of China Editorial Committee (2017):

Perennial. Culms slender, tufted, usually geniculate at base, 20-100 cm tall. Leaf sheaths keeled; leaf blades flat or folded, 10-20 × 0.3-0.6 cm, scabrid or adaxial surface pilose at base, apex obtuse or shortly acute to apiculate; ligule ciliate along margin. Inflorescence terminal or racemes gathered into a scanty panicle; spatheoles linear, tightly rolled around peduncle; peduncles mostly long-exserted. Racemes 3-7 cm (excluding awns), narrowly cylindrical, 7-12-awned, (1-)3-10(-12) pairs of flat green homogamous spikelets below the awned fertile pairs. Sessile spikelet 5-7 mm, dark brown; callus 2-3 mm, fiercely pungent, brown bearded; lower glume linear becoming cylindrical at maturity, sometimes hispidulous between veins; awn 6-10 cm, dark brown, column white-hirtellous, tips of successive awns often twisting together. Pedicelled spikelet 6-11 mm, lower glume oblong-lanceolate, greenish, laterally asymmetrically winged, glabrous or sparsely to densely pilose or tuberculate-hispid or white setose. Fl. and fr. Apr-Dec.

Plant Type

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Grass / sedge
Herbaceous
Perennial
Seed propagated
Vegetatively propagated

Distribution

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H. contortus is native to Africa, temperate and tropical Asia, Australasia and southwestern Europe, and is naturalized in southern USA, Mexico, the Caribbean, Central and South America (USDA-ARS, 2017). It is reported as naturalized in Hawaii by USDA-ARS (2017) but according to University of Hawaii (2009), it is not clear whether H. contortus is indigenous to Hawaii or a Polynesian introduction.

USDA-ARS (2017) and Baldwin et al. (2012) report H. contortus as an alien species in California, USA, but according to Calflora (2017), it is native in California.

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 19 Aug 2020
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes

Africa

AlgeriaPresentNative
AngolaPresentNative
BeninPresentNative
Cabo VerdePresentNative
CameroonPresentNative
Central African RepublicPresentNative
ChadPresentNative
Congo, Democratic Republic of thePresentNative
Congo, Republic of thePresentNative
Côte d'IvoirePresentNative
EritreaPresentNative
EthiopiaPresentNative
GabonPresentNative
GhanaPresentNative
GuineaPresentNative
KenyaPresentNative
LiberiaPresentNative
LibyaPresentNative
MaliPresentNative
MauritaniaPresentNative
MoroccoPresentNative
MozambiquePresentNative
NigerPresentNative
NigeriaPresentNative
RwandaPresentNative
SenegalPresentNative
Sierra LeonePresentNative
SomaliaPresentNative
South AfricaPresentNative
SudanPresentNative
TanzaniaPresentNative
TogoPresentNative
TunisiaPresentNative
UgandaPresentNative
ZambiaPresentNative
ZimbabwePresentNative

Asia

China
-FujianPresentNative
-GansuPresentNative
-GuangdongPresentNative
-GuangxiPresentNative
-GuizhouPresentNative
-HainanPresentNative
-HenanPresentNative
-HubeiPresentNative
-HunanPresentNative
-JiangxiPresentNative
-ShaanxiPresentNative
-SichuanPresentNative
-YunnanPresentNative
-ZhejiangPresentNative
IndiaPresentNative
LebanonPresentNative
MyanmarPresentNative
Sri LankaPresentNative
SyriaPresentNative

Europe

AlbaniaPresentNative
CroatiaPresentNative
FrancePresentNative
ItalyPresentNative
MontenegroPresentNative
SpainPresentNative

North America

CubaPresentIntroducedInvasive
El SalvadorPresentIntroduced
GuatemalaPresentIntroduced
HondurasPresentIntroduced
MexicoPresentIntroduced
NicaraguaPresentIntroduced
United States
-ArizonaPresentIntroduced
-CaliforniaPresentIntroduced
-FloridaPresentIntroduced
-HawaiiPresentIntroduced
-New MexicoPresentIntroduced
-TexasPresentIntroduced

Oceania

AustraliaPresentNative
-New South WalesPresentNative
-Northern TerritoryPresentNative
-QueenslandPresentNative
-Western AustraliaPresentNative
New CaledoniaPresentIntroducedInvasive

South America

ArgentinaPresentIntroduced
BoliviaPresentIntroduced

Habitat

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Prairies, plains, meadows, pastures and savannahs are native habitats for H. contortus (Lady Bird Johnson Wildflower Center, 2017). In Hawaii, it is found on dry rocky cliffs, ledges or slopes close to ocean exposure (Wagner et al., 1990). It has been displaced by alien grasses and shrubs so is less common than in the past and seems to be disappearing in Oʻahu and Moloka’i (University of Hawaii, 2009).

In Texas, USA, H. contortus is found in the Trans-Pecos Mountains, sandy prairies, coastal regions and also persists in well-managed pastures (Reilly et al., 2002).

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial ManagedManaged grasslands (grazing systems) Present, no further details
Terrestrial ManagedDisturbed areas Present, no further details
Terrestrial ManagedRail / roadsides Present, no further details
Terrestrial Natural / Semi-naturalNatural forests Principal habitat
Terrestrial Natural / Semi-naturalNatural grasslands Principal habitat

Biology and Ecology

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H. contortus grows on a wide variety of well-drained soils but it is less common on heavy clay soils. It is most abundant in areas where the average annual rainfall is 600-1000 mm but is also found on the big island of Hawaii which receives 211 mm annual rainfall, and in an area of eastern Argentina receiving over 1500 mm/year. It does not tolerate long periods of flooding or waterlogging.

Plants are largely dormant during the cooler and drier months. Vegetative growth resumes when both soil moisture level and temperature are adequate. H. contortus can tolerate light shade and moderate frost (Tropical Forages, 2017).

Genetics

2n=39, 40, 50, 60, 69, 70, 80, 90. Tropical genotypes are predominantly tetraploid, whereas subtropical genotypes range from tetraploid to nonaploid (Tropical Forages, 2017).

Reproductive Biology

H. contortus can reproduce from seeds or vegetative transplants. When the seeds come in contact with moisture, the sharp tips and awns twist, planting them into the soil. Reproduction is largely through aposporous apomixis. Sexual reproduction does occur but the percentage is very low, about 15% (Tropical Forages, 2017).

The seeds have a dormant period of about 6 months. Although the seeds will germinate before dormancy, the germination rate is very low. Germination should occur within 5-7 days (Reilly et al., 2002).

Longevity

H. contortus is a short-lived, perennial plant, with a lifespan of less than 5 years (University of Hawaii, 2009). Under light grazing, individual plants can live for several years.

Physiology and Phenology

Pan-tropical populations of H. contortus flower late, whereas subtropical populations comprise early to late flowering types. Flowering can be delayed by poor soil moisture, even when day length is suitable (Tropical Forages, 2017). University of Hawaii (2009) note that H. contortus blooms throughout the year.

Associations

H. contortus grows naturally with Themeda triandra, Bothriochloa bladhii and Hyparrhenia spp. It is also found growing with legumes Aeschynomene falcata, Chamaecrista pilosa, C. rotundifolia, Lotononis bainesii, Macroptilium atropurpureum, Stylosanthes guianensis var. intermedia [S. montevidensis var. intermedia], S. hamata, S. humilis and S. scabra (Tropical Forages, 2017).

In Australia, H. contortus grows in the understorey of various eucalypt woodlands: dominant overstorey of silver-leaved ironbark (Eucalyptus melanophloia), narrow-leaved ironbark (E. crebra), spotted gum (E. maculata [Corymbia maculata]) and blue gum (E. tereticornis) in Queensland. In the Northern Territory the dominant overstories are E. tetrodonta and E. dichromophloia [Corymbia dichromophloia]. Eragrostis, Aristida, Chloris and Chrysopogon also grow with H. contortus (NSW Government Department of Primary Industries, 2017).

In Hawaii, H. contortus has been outcompeted by foreign grassland species such as Cenchrus ciliaris (buffel grass), Pennisetum setaceum (fountain grass) and Panicum maximum (guinea grass) (Heuzé et al., 2017).

Environmental Requirements

H. contortus can tolerate drought, wind, salt spray and heat. It prefers full sun to partial sun (University of Hawaii, 2009). It prefers to stay dry but can tolerate both dry and moist conditions.

Sandy loams of pH 5.0-6.0 are preferred (PROTA, 2017). H. contortus is much less common on heavy clay soils and in saline situations (NSW Government Department of Primary Industries, 2017).

Climate

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ClimateStatusDescriptionRemark
As - Tropical savanna climate with dry summer Preferred < 60mm precipitation driest month (in summer) and < (100 - [total annual precipitation{mm}/25])
Aw - Tropical wet and dry savanna climate Preferred < 60mm precipitation driest month (in winter) and < (100 - [total annual precipitation{mm}/25])
Cs - Warm temperate climate with dry summer Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers
B - Dry (arid and semi-arid) Preferred < 860mm precipitation annually

Latitude/Altitude Ranges

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
46.13 38.24

Rainfall

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ParameterLower limitUpper limitDescription
Mean annual rainfall6001000mm; lower/upper limits

Rainfall Regime

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Bimodal
Summer
Winter

Soil Tolerances

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Soil drainage

  • free

Soil reaction

  • acid
  • alkaline

Soil texture

  • heavy
  • light
  • medium

Special soil tolerances

  • saline
  • sodic

Natural enemies

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Natural enemyTypeLife stagesSpecificityReferencesBiological control inBiological control on
Atherigona oryzae Pathogen
Claviceps pusilla Pathogen
Peronosclerospora sorghi Pathogen

Notes on Natural Enemies

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H. contortus is occasionally attacked by insects (scales, mealybugs, locusts and grasshoppers) but is otherwise generally pest free (University of Hawaii, 2009). It is also damaged by various fungi. Smut diseases caused by Sorosporium antheseriae, S. caledonicum [Anthracocystis caledonica], Sphacelotheca monilifera [Sporisorium moniliferum] and Urocystis skirgielloae affect seed production. Seed production is also reduced by ergot (Claviceps pusilla, C. sorghi). Leaf rust, caused by Puccinia versicolor or Uromyces clignyi, is common on mature leaves. Sclerophthora cryophila has been isolated from leaf spots on H. contortus in India. H. contortus acts as a collateral host for a downy mildew, caused by Peronosclerospora sorghi (P. heteropogonis) (Tropical Forages, 2017).

H. contortus has been outcompeted by foreign grassland species such as Cenchrus ciliaris (buffel grass), Pennisetum setaceum (fountain grass) and Panicum maximum (guinea grass) in Hawaii (Heuzé et al., 2017).

Means of Movement and Dispersal

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The harpoon-like attachments on the seeds can become attached to fur and feathers (University of Hawaii, 2009) and clothing, which facilitates dispersal of the seed (Ansong and Pickering, 2013).

Pathway Causes

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CauseNotesLong DistanceLocalReferences
Internet sales Yes Yes
Ornamental purposes Yes Yes
Seed trade Yes Yes

Pathway Vectors

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Impact Summary

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CategoryImpact
Cultural/amenity Positive
Economic/livelihood Positive and negative
Environment (generally) Positive
Human health Positive and negative

Economic Impact

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According to Wikipedia, the wool industry has been eliminated in parts of Australia due to the impact of H. contortus. Harpoon-like attachments on the seeds can become embedded in the wool and skin of sheep, which devalues the wool and can kill the animals.

Environmental Impact

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H. contortus is used for ecosystem restoration and revegetation of degraded habitats. It also provides nesting cover for birds and fawning cover for deer (Reilly et al., 2002).

Impact: Biodiversity

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H. contortus has the potential to increase diversity in riparian and other communities (Reilly et al., 2002).

In Zambia, bees were observed visiting H. contortus for pollen (Brink and Achigan-Dako, 2012).

Risk and Impact Factors

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Invasiveness
  • Has a broad native range
  • Abundant in its native range
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Pioneering in disturbed areas
  • Tolerant of shade
  • Reproduces asexually
  • Has high genetic variability
Impact outcomes
  • Ecosystem change/ habitat alteration
  • Negatively impacts human health
  • Negatively impacts animal health
  • Negatively impacts livelihoods
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Highly likely to be transported internationally deliberately

Uses

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H. contortus is used as a summer fodder pasture. It is also used for thatching, matting and making cellulose for paper. The leaves have been used to stuff mattresses and pad floors.

The interesting seed head makes H. contortus a good ornamental plant (Reilly et al., 2002). In South Africa, Zulu people use H. contortus to treat rheumatism, burns and wounds (Brink and Achigan-Dako, 2012).

Burning is commonly used method to maintain H. contortus pastures for grazing. The grazing fields should be burned on an annual basis to reduce dead plant matter and induce new growth, but burning during the dry season may reduce nutrient availability. If H. contortus is consistently grazed, it does not develop seeds but populations will decrease if grazing is too heavy (Reilly et al., 2002).

Economic Value

H. contortus is a good forage grass for the south-western USA (Reilly et al., 2002).

Social Benefit

In Hawaii, burned plant and its ashes mixed with coconut has been used to treat thrush and childhood disease with physical weakening. A black dye can be made from the charcoaled leaf blades.

Environmental Services

Moata (2009) reported the use of H. contortus as a living mulch for tropical vegetable crops in Hawaii. It influenced crop growth by: increasing weed suppression; increasing the population and biodiversity of insects; increasing nitrogen levels; improving soil structure (aggregate stability); maintaining soil moisture and cooler soil temperatures; reducing the effects of pests and diseases; with no clear detectable toxic compounds. Climatic conditions also influenced crop growth (Moata, 2009). H. contortus has also been used in conservation efforts on Kaho'olawe, Hawaii, and as a roadside grass to displace invasive species along local transportation corridors (University of Hawaii, 2009).

In drylands of Zimbabwe, H. contortus has been used to increase greenery in desertified areas and to increase carbon sequestration. In the USA, a cultivar of H. contortus was recommended for erosion control along roadways, construction sites and other disturbed areas in the southwest desert, and also for revegetation (Pater, 1995). In India, it has been used to prevent erosion on up to 20° slopes (Heuzé et al., 2017).

Uses List

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Animal feed, fodder, forage

  • Forage

Environmental

  • Erosion control or dune stabilization
  • Landscape improvement
  • Soil conservation

Materials

  • Dyestuffs

Medicinal, pharmaceutical

  • Source of medicine/pharmaceutical

Ornamental

  • Potted plant
  • Seed trade

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

H. contortus is susceptible to grazing in the early part of the wet season. It is also susceptible to glyphosate (Tropical Forages, 2017).

References

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Ansong, M., Pickering, C., 2013. Long-distance dispersal of Black Spear Grass (Heteropogon contortus) seed on socks and trouser legs by walkers in Kakadu National Park. Ecological Management & Restoration, 14(1), 71-74. doi: 10.1111/emr.12021

Baldwin, BG, Goldman, DH, Keil, DJ, Patterson, R, Rasatti, TJ, Wilken, DH, 2012. The Jepson manual: vascular plants of California. Berkeley, California, USA: University of California Press.

Brink M, Achigan-Dako EG, 2012. Plant Resources of Tropical Africa 16. Fibres, Wageningen, Netherlands: PROTA Foundation/CTA.602 pp.

Calflora, 2017. Calflora: Information on California plants for education, research, and conservation. In: Calflora: Information on California plants for education, research, and conservation Berkeley, California, USA: Calflora Database.http://www.calflora.org

CDFA, 2017. California, USA: California Department of Food & Agriculture.https://www.cdfa.ca.gov/plant/ipc/encycloweedia/weedinfo/winfo_table-sciname.html

Flora of China Editorial Committee, 2017. Flora of China. In: Flora of China St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria.http://www.efloras.org/flora_page.aspx?flora_id=2

Heuzé V, Tran G, Giger-Reverdin S, Lebas F, 2017. Spear grass (Heteropogon contortus). In: Feedipedia, a programme by INRA, CIRAD, AFZ and FAO, INRA, CIRAD, AFZ, FAO.https://www.feedipedia.org/node/433

ISSG, 2017. Global Invasive Species Database (GISD). In: Global Invasive Species Database (GISD) : Invasive Species Specialist Group of the IUCN Species Survival Commission.http://www.issg.org/database/welcome/

Lady Bird Johnson Wildflower Center, 2017. Heteropogon contortus. Austin, Texas, USA: Lady Bird Johnson Wildflower Center.http://www.wildflower.org/plants/result.php?id_plant=HECO10

Moata, MRS, 2009. Characterizing piligrass (Heteropogon contortus) as living mulch for tropical vegetable crops. Manoa, Hawaii, USA: Department of Tropical Plant and Soil Sciences, Universitas of Hawai’i at Manoa-USA. https://www.ctahr.hawaii.edu/defrankJ/Text%20resources/Living_mulch_2009/M_Moata_thesis_11_24_2009.pdf

NSW Government Department of primary Industries, 2017. Heteropogon contortus (Black speargrass). New South Wales, Australia: NSW Government Department of primary Industries.http://www.dpi.nsw.gov.au/agriculture/pastures-and-rangelands/rangelands/publications-and-information/grassedup/species/speargrass

Oviedo Prieto, R., Herrera Oliver, P., Caluff, M. G., et al., 2012. National list of invasive and potentially invasive plants in the Republic of Cuba - 2011. (Lista nacional de especies de plantas invasoras y potencialmente invasoras en la República de Cuba - 2011). Bissea: Boletín sobre Conservación de Plantas del Jardín Botánico Nacional de Cuba, 6(Special Issue No. 1), 22-96.

Pater MJ, 1995. ‘Rocker’ Tanglehead (Heteropogon contortus [L.] Beauv. ex Roem. and J. A. Schultes): An improved cultivar for conservation. In: Proceedings of the Wildland shrub and arid land restoration symposium 19-21 October 1993 [ed. by Roundy BA, McArthur ED, Haley JS, Mann DK]. Las Vegas, USA

PROTA, 2017. PROTA4U web database. In: PROTA4U web database Wageningen and Nairobi, Netherlands\Kenya: Plant Resources of Tropical Africa.https://www.prota4u.org/database/

Reilly J, Maher SD, Duvauchelle D, 2002. Tanglehead Heteropogon contortus (L.) P. Beauv. ex Roem. & Schult. In: Plant Fact Sheet, USA: USDA-NRCS.https://plants.usda.gov/factsheet/pdf/fs_heco10.pdf

Tropical Forages, 2017. Tropical forages: an interactive selection tool. http://www.tropicalforages.info/index.htm

University of Hawaii, 2009. Heteropogon contortus. In: Native Plants Hawaii, Hawaii, USA: University of Hawaii.http://nativeplants.hawaii.edu/plant/view/Heteropogon_contortus

USDA-ARS, 2017. Germplasm Resources Information Network (GRIN). Online Database. In: Germplasm Resources Information Network (GRIN). Online Database Beltsville, Maryland, USA: National Germplasm Resources Laboratory.https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysimple.aspx

Wagner WL, Herbst DR, Sohmer SH, 1990. Manual of Flowering Plants of Hawaii. Vol 2. Bernice Pauahi Bishop Museum Special Publication 83, Honolulu, Hawaii, USA: University of Hawaii Press.

World Flora Online, 2020. World Flora Online. In: World Flora Online : World Flora Online Consortium.http://www.worldfloraonline.org

Distribution References

Baldwin BG, Goldman DH, Keil DJ, Patterson R, Rasatti TJ, Wilken DH, 2012. The Jepson manual: vascular plants of California., Berkeley, California, USA: University of California Press.

Calflora, 2017. Calflora: Information on California plants for education, research, and conservation. In: Calflora: Information on California plants for education, research, and conservation. Berkeley, California, USA: Calflora Database. http://www.calflora.org

ISSG, 2017. Global Invasive Species Database (GISD). In: Global Invasive Species Database (GISD). Invasive Species Specialist Group of the IUCN Species Survival Commission. http://www.issg.org/database/welcome/

Moata MRS, 2009. Characterizing piligrass (Heteropogon contortus) as living mulch for tropical vegetable crops. Manoa, Hawaii, USA: Department of Tropical Plant and Soil Sciences, Universitas of Hawai’i at Manoa-USA. https://www.ctahr.hawaii.edu/defrankJ/Text%20resources/Living_mulch_2009/M_Moata_thesis_11_24_2009.pdf

Oviedo Prieto R, Herrera Oliver P, Caluff M G, et al, 2012. National list of invasive and potentially invasive plants in the Republic of Cuba - 2011. (Lista nacional de especies de plantas invasoras y potencialmente invasoras en la República de Cuba - 2011). Bissea: Boletín sobre Conservación de Plantas del Jardín Botánico Nacional de Cuba. 6 (Special Issue No. 1), 22-96.

USDA-ARS, 2017. Germplasm Resources Information Network (GRIN). Online Database. In: Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysimple.aspx

Links to Websites

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WebsiteURLComment
GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gatewayhttps://doi.org/10.5061/dryad.m93f6Data source for updated system data added to species habitat list.

Contributors

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02/04/17 Original text by:

Shruti Dube, Department of Botany-Smithsonian NMNH, Washington DC, USA

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