Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Datasheet

Tragus racemosus
(stalker bur grass)

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Datasheet

Tragus racemosus (stalker bur grass)

Summary

  • Last modified
  • 11 November 2021
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Tragus racemosus
  • Preferred Common Name
  • stalker bur grass
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Monocotyledonae
  • Summary of Invasiveness
  • Tragus racemosus is an annual grass native to Europe, Asia and Africa. It is listed as an invasive species in Cuba, being naturalized from the central part of the country to the eastern provinces. Although this species is reported as not...

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Pictures

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PictureTitleCaptionCopyright
Tragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.
TitleHabit
CaptionTragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.
HabitTragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.
TitleHabit
CaptionTragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.
HabitTragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Hochleithen, Mistelbach, Austria. September 2020.
TitleHabit
CaptionTragus racemosus; Habit. Hochleithen, Mistelbach, Austria. September 2020.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Hochleithen, Mistelbach, Austria. September 2020.
HabitTragus racemosus; Habit. Hochleithen, Mistelbach, Austria. September 2020.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Plant. Lim Bay, Jural, Croatia. September 2018.
TitlePlant
CaptionTragus racemosus; Plant. Lim Bay, Jural, Croatia. September 2018.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Plant. Lim Bay, Jural, Croatia. September 2018.
PlantTragus racemosus; Plant. Lim Bay, Jural, Croatia. September 2018.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.
TitleHabit
CaptionTragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.
HabitTragus racemosus; Habit. Gaweinstal, Mistelbach, Austria. October 2020.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Hochleithen, Mistelbach, Austria. October 2020.
TitleHabit
CaptionTragus racemosus; Habit. Hochleithen, Mistelbach, Austria. October 2020.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Hochleithen, Mistelbach, Austria. October 2020.
HabitTragus racemosus; Habit. Hochleithen, Mistelbach, Austria. October 2020.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Plant. Hochleithen, Mistelbach, Austria. October 2020.
TitlePlant
CaptionTragus racemosus; Plant. Hochleithen, Mistelbach, Austria. October 2020.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Plant. Hochleithen, Mistelbach, Austria. October 2020.
PlantTragus racemosus; Plant. Hochleithen, Mistelbach, Austria. October 2020.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Plant. Gaweinstal, Mistelbach, Austria. October 2020.
TitlePlant
CaptionTragus racemosus; Plant. Gaweinstal, Mistelbach, Austria. October 2020.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Plant. Gaweinstal, Mistelbach, Austria. October 2020.
PlantTragus racemosus; Plant. Gaweinstal, Mistelbach, Austria. October 2020.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Hochleithen, Mistelbach, Austria. September 2020.
TitleHabit
CaptionTragus racemosus; Habit. Hochleithen, Mistelbach, Austria. September 2020.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Habit. Hochleithen, Mistelbach, Austria. September 2020.
HabitTragus racemosus; Habit. Hochleithen, Mistelbach, Austria. September 2020.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Leaf sheath with ciliate ligule and leaf with setae on the margin. Lim Bay, Jural, Croatia. September 2018.
TitleLeaf sheath
CaptionTragus racemosus; Leaf sheath with ciliate ligule and leaf with setae on the margin. Lim Bay, Jural, Croatia. September 2018.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Leaf sheath with ciliate ligule and leaf with setae on the margin. Lim Bay, Jural, Croatia. September 2018.
Leaf sheathTragus racemosus; Leaf sheath with ciliate ligule and leaf with setae on the margin. Lim Bay, Jural, Croatia. September 2018.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Leaf sheath with ciliate ligule and leaf with setae on the margin. Lim Bay, Jural, Croatia. September 2018.
TitleLeaf sheath
CaptionTragus racemosus; Leaf sheath with ciliate ligule and leaf with setae on the margin. Lim Bay, Jural, Croatia. September 2018.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Leaf sheath with ciliate ligule and leaf with setae on the margin. Lim Bay, Jural, Croatia. September 2018.
Leaf sheathTragus racemosus; Leaf sheath with ciliate ligule and leaf with setae on the margin. Lim Bay, Jural, Croatia. September 2018.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Panicle. Lim Bay, Jural, Croatia. September 2018.
TitlePanicle
CaptionTragus racemosus; Panicle. Lim Bay, Jural, Croatia. September 2018.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Panicle. Lim Bay, Jural, Croatia. September 2018.
PanicleTragus racemosus; Panicle. Lim Bay, Jural, Croatia. September 2018.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Spikelets. Lim Bay, Jural, Croatia. September 2018.
TitleSpikelets
CaptionTragus racemosus; Spikelets. Lim Bay, Jural, Croatia. September 2018.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Spikelets. Lim Bay, Jural, Croatia. September 2018.
SpikeletsTragus racemosus; Spikelets. Lim Bay, Jural, Croatia. September 2018.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Labelled spikelet showing: Glu = Glume,
Lem = Lemma, Pal = Palea. Lim Bay, Jural, Croatia. September 2018.
TitleSpikelet detail
CaptionTragus racemosus; Labelled spikelet showing: Glu = Glume, Lem = Lemma, Pal = Palea. Lim Bay, Jural, Croatia. September 2018.
Copyright©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0
Tragus racemosus; Labelled spikelet showing: Glu = Glume,
Lem = Lemma, Pal = Palea. Lim Bay, Jural, Croatia. September 2018.
Spikelet detailTragus racemosus; Labelled spikelet showing: Glu = Glume, Lem = Lemma, Pal = Palea. Lim Bay, Jural, Croatia. September 2018.©Stefan Lefnaer (Stefan.lefnaer)/via Wikimedia Commons - CC BY-SA 4.0

Identity

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Preferred Scientific Name

  • Tragus racemosus (L.) All.

Preferred Common Name

  • stalker bur grass

Other Scientific Names

  • Cenchrus racemosus L.
  • Lappago decipiens Fig. & De Not.
  • Lappago racemosa (L.) Honck.
  • Nazia racemosa (L.) Kuntze
  • Tragus adriaticus Gand.
  • Tragus arenarius Bremek. & Oberm.
  • Tragus brevicaulis Boiss.
  • Tragus decipiens (Fig. & De Not) Boiss.
  • Tragus echinatus Cav.
  • Tragus pallens Gand.
  • Tragus paucispinus Hack.

International Common Names

  • English: carrot seed grass; European bur grass; large carrot-seed grass; spike bur grass

Local Common Names

  • Cuba: rabo de gato
  • France: tragus à grappes
  • Germany: Klettengras
  • Italy: lappola
  • South Africa: wortelsaadgras
  • Spain: cerretes; escanyyagats; grama enmarañada
  • Sweden: piprensargräs

Summary of Invasiveness

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Tragus racemosus is an annual grass native to Europe, Asia and Africa. It is listed as an invasive species in Cuba, being naturalized from the central part of the country to the eastern provinces. Although this species is reported as not affecting crops it is very competitive in dry and nutrient-poor soils. T. racemosus is also listed as invasive in Belgium and Serbia but without further details given. Although considered as a rare and ephemeral alien species in Belgium, it is recognized that this species is spreading fast from southern Europe and becoming abundant at some disturbed areas. T. racemosus is also described as a prostrate weed of warm semiarid areas.

Taxonomic Tree

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

Notes on Taxonomy and Nomenclature

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Tragus is a genus in the Poaceae family with seven to eight accepted species, mostly tropical and subtropical (Anton, 1981; World Flora Online, 2020). The genus is characterized by having a disarticulating inflorescence, a rudimentary first glume and an awnless second glume with distinctive prickles or spines on its nerves (Anton, 1981).

The genus name Tragus comes from the Greek word ‘tragos’ meaning he-goat and the specific epithet ‘racemosus’ refers to the racemose inflorescence (SEINet, 2020). Of the synonyms reported for T. racemosus, Aira malatrina, Cenchrus linearis, Lappago biflora, Phalaris muricata, T. biflorus and T. muricatus are invalid names; T. halleri and T. orientalis are illegitimate names (World Flora Online, 2020).

Description

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The following description is from PROTA (2020):

Annual up to 25 cm tall, erect or geniculately ascending; leaf laminas 2-6 cm × 1.5-4.5 mm, flat or plicate, glaucous, the margins thickened, whitish, pectinate with bulbous-based hairs or barbellate. Inflorescence 2.5-6 cm long, compactly cylindrical, congested; racemelets comprising (1)2-4 fertile and (1)2 sterile spikelets borne on a short peduncle. Spikelets 3.2-4 mm long; superior glume prominently 7-nerved, the nerves bearing hooked, bulbous-based prickles, glabrous between the nerves; anthers 0.5-0.7 mm long.

Plant Type

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Annual
Grass / sedge
Herbaceous
Seed / spore propagated

Distribution

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Tragus racemosus is a small ephemeral grass native to arid areas, deserts, semi-desert and semiarid continental areas of Africa, Asia and Europe (Kalapos et al., 1996; Shabana et al., 2018; Native Plant Trust, 2020; PROTA, 2020; SEINet, 2020; USDA-ARS, 2020). Its native distribution in Europe is restricted to the semiarid continental climate of Europe where it grows only during the hot and dry months (Kalapos et al., 1996). It has been introduced to the New World accidentally as a contaminant of wool products (Native Plant Trust, 2020).

Tragus racemosus is reported in Asia, Africa, Europe, North America, the Caribbean and South America (Fasseaux, 1949; Harsh and Sen, 1975; Proctor, 1982; Sulekic and Zapater, 2001; E-Flora of South Africa, 2020; Euro+Med, 2020; India Biodiversity Portal, 2020; Missouri Botanical Garden, 2020; PROTA, 2020; SEINet, 2020; USDA-ARS, 2020).

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: 17 Dec 2021
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes

Africa

AlgeriaPresentNative
AngolaPresentNative
BotswanaPresentNative
Cabo VerdePresentNative
Central African RepublicPresentNative
EgyptPresentNative
EthiopiaPresentNative
LesothoPresentNative
LibyaPresentIntroduced1984Sources differ as to whether it is native or introduced
MaliPresentNative
MauritaniaPresentNative
MoroccoPresentNative
NamibiaPresentNative
SenegalPresentNative
SomaliaPresentNative
South AfricaPresentNative
SudanPresentNative
TunisiaPresentNative
ZimbabwePresentNative

Asia

AfghanistanPresentNative
ArmeniaPresentNative
AzerbaijanPresentNative
ChinaAbsent, Invalid presence record(s)Misidentified record
GeorgiaPresentNative
IndiaPresentNative
-RajasthanPresentNativeEphemeral. Appears with the start of the rainy season and disappears in late August
-Uttar PradeshPresentNative
IranPresentNative
KazakhstanPresentNative
KyrgyzstanPresentIntroduced
LebanonPresentNative
OmanPresentNative
PakistanPresentOccurrence rare, available during monsoon season for grazing by camels in Cholistan desert
Saudi ArabiaPresentNative
SyriaPresentNative
ThailandPresentNative
TurkeyPresentNative
United Arab EmiratesPresentNative
YemenPresentNative

Europe

AlbaniaPresentNative
AustriaPresentIntroduced1872Urban areas, agricultural areas, disturbed areas, grass and heathlands
BelgiumPresentIntroducedInvasive
BulgariaPresentNative
CroatiaPresentNative
CzechiaPresentNative
FrancePresentNative
-CorsicaPresentNative
GermanyPresentIntroduced
GreecePresentNative
HungaryPresentNative
ItalyPresentNative
MaltaPresentNative
MoldovaPresent
NetherlandsPresentIntroducedCasual
PolandPresentIntroducedCasual
RomaniaPresentNative
RussiaPresentNative
SerbiaPresentInvasive
SlovakiaPresentNative
SloveniaPresentNative
SpainPresentNative
-Balearic IslandsPresentNative
-Canary IslandsPresentNative
SwitzerlandPresentNative
UkrainePresentIntroduced
United KingdomAbsent, Formerly presentRecorded from the wild by 1908. Does not appear to have been recorded recently

North America

CubaPresentIntroducedInvasive
JamaicaPresentIntroduced1954
United StatesPresentIntroduced
-ArizonaPresentIntroducedPrimarily in Cochise and Pima counties
-DelawarePresentIntroduced
-MaineAbsent, Formerly present
-MarylandPresentIntroduced1953
-MassachusettsPresentIntroduced1882Boston flats. As a fugitive plant
-New JerseyPresentIntroduced
-New MexicoAbsent, Formerly present
-New YorkAbsent, Formerly present
-North CarolinaAbsent, Invalid presence record(s)Confused with T. berteronianus
-PennsylvaniaAbsent, Formerly present
-TexasAbsent, Formerly present
-VirginiaPresentIntroduced

Oceania

AustraliaAbsent, Invalid presence record(s)A misidentification of T. australiensis

South America

ArgentinaPresentIntroducedOccasional
BoliviaPresentIntroduced
PeruPresentIntroduced

History of Introduction and Spread

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Tragus racemosus is reported as present in Belgium prior to 1850, as a common wool alien from 1887 to 1947. In recent times, it has been found in disturbed sites near railways (Alien plants of Belgium, 2020) and reported to be spreading rapidly in southern Europe, with stable populations found in northern France. Diaspores of T. racemosus were introduced into the Czech Republic with wool into local woollen mills, and spread to the surrounding areas via wool waste (Kaplan et al., 2015). Although T. racemosus is reported as native to Africa, it is listed in Libya as both native and introduced (El-Gadi et al., 1987).

In the USA, T. racemosus has been reported since the late 1800s in the northeast as a ballast waif and as growing in dumps of wool carding factories (Knowlton et al., 1913; Pohl, 1947; Native Plant Trust, 2020). It has spread to the western USA from Arizona to Texas and in the eastern USA from Maine to North Carolina, but without details given (Reed, 1954). According to SEINet (2020), the species was collected in Maine, Pennsylvania, New York and North Carolina in the late 19th century, but is no longer present in those states. It is considered as an occasional anthropogenic weed in eastern USA (Native Plant Trust, 2020). From its distribution in the western USA, some of the reports for New Mexico and Texas appear to be misidentifications of T. berteronianus (SEINet, 2020). In the New World, it is also known to occur in South America since the mid-1800s and in the Caribbean in the 1950s (Proctor, 1982; Missouri Botanical Garden, 2020).

Introductions

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Introduced toIntroduced fromYearReasonIntroduced byEstablished in wild throughReferencesNotes
Natural reproductionContinuous restocking
Libya 1984 Yes No El-Gadi et al. (1987)
USA 1879 Hitchhiker (pathway cause) Yes No Pohl (1947)
Jamaica 1954 Yes No Proctor (1982)
Bolivia 1848-1861 No No Missouri Botanical Garden (2020)
Belgium Prior to 1850 Hitchhiker (pathway cause) Yes No Alien plants of Belgium (2020)
Germany 1900 No No Missouri Botanical Garden (2020) Seeds?

Risk of Introduction

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There is not enough information on the biology of the species and its environmental requirements to fully assess the risk of introduction of T. racemosus. This species is not actively used for forage due to its low stature, low yield and ephemeral nature (PROTA, 2020). It is also unlikely to be introduced to any country as an ornamental, or for any economic or social benefits. At present, T. racemosus has a medium risk of introduction due to the potential for accidental introductions through wool products (Alien plants of Belgium, 2020PROTA, 2020; SEINet, 2020).

Habitat

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Tragus racemosus is an annual prostrate grass reported from wooded grasslands, dwarf shrublands, river margins. roadsides, railroads, waste and disturbed areas, savannahs, sand steppes, coastal sandy areas away from the littoral zone, ruderal areas and dry creek beds, from near sea level to 1800 m elevation (Weare and Yalala, 1971; Gibbs Russell and Biegel, 1973; Lawesson, 1990; Palmer, 1991; Jabbour et al., 1996; Moore et al., 2016; García-Lahera and Morgado, 2018; E-Flora of South Africa, 2020; PROTA, 2020).

Habitat List

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial ManagedDisturbed areas Present, no further details Natural
Terrestrial ManagedRail / roadsides Present, no further details Natural
Terrestrial ManagedUrban / peri-urban areas Present, no further details Natural
Terrestrial Natural / Semi-naturalNatural grasslands Present, no further details Natural
Terrestrial Natural / Semi-naturalRiverbanks Present, no further details Natural
Terrestrial Natural / Semi-naturalRocky areas / lava flows Present, no further details Natural
Terrestrial Natural / Semi-naturalScrub / shrublands Present, no further details Natural
Terrestrial Natural / Semi-naturalDeserts Present, no further details Natural
Terrestrial Natural / Semi-naturalArid regions Present, no further details Natural
LittoralCoastal areas Present, no further details Natural

Hosts/Species Affected

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Catasús Guerra (2015) reports T. racemosus as not affecting crops in Cuba.

Biology and Ecology

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Genetics

Germplasm collections of T. racemosus are available at USDA facilities and at the Millennium Seed Bank (Kew Royal Botanic Gardens, 2020; USDA-ARS, 2020). The chromosome number reported for the species is 2n = 40 (PROTA, 2020).

Reproductive Biology

Tragus racemosus is an ephemeral grass that reproduces by seed (PROTA, 2020). A 75% germination rate and 100% seed viability are reported for the species at the Millennium Seed Bank (Kew Royal Botanic Gardens, 2020). T. racemosus is also reported as having a low seed yield (PROTA, 2020).

Physiology and Phenology

Tragus racemosus is a small annual prostrate C4 grass (Kalapos, 1991). This species has a short life cycle, with seeds germinating in June, and plants flowering and fruiting from July to September and dying in the first frosts (Jabbour et al., 1996; Catasús Guerra, 2015; E-Flora of South Africa, 2020). Seeds are reported to have a short-lived persistence in soil (Johannsmeier, 2009).

Longevity

Tragus racemosus is an annual prostrate grass with a short growth cycle (PROTA, 2020).

Activity Patterns

Tragus racemosus is reported as being an early successional species (Kalapos et al., 1996).

Environmental Requirements

There is very little information available on the environmental requirements of T. racemosus. The species is reported as growing in all soil types, especially dry sandy soils with low nutrients and low humus (Obeid and Mahmoud, 1969; Leistner and Werger, 1973; Jabbour et al., 1996; Kalapos et al., 1996; E-Flora of South Africa, 2020; PROTA, 2020). It has high temperature requirements and will not survive frosts (Jabbour et al., 1996). T. racemosus is reported as growing in arid hot deserts, semi-deserts and semiarid continental climates (Kalapos et al., 1996; Shabana et al., 2018).

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])
BS - Steppe climate Preferred > 430mm and < 860mm annual precipitation
BW - Desert climate Preferred < 430mm annual precipitation
Cs - Warm temperate climate with dry summer Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, dry summers
Cf - Warm temperate climate, wet all year Preferred Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year

Latitude/Altitude Ranges

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
50 37

Air Temperature

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Parameter Lower limit Upper limit
Mean annual temperature (ºC) 10 35

Rainfall

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ParameterLower limitUpper limitDescription
Mean annual rainfall125 975 mm; lower/upper limits

Rainfall Regime

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Summer
Uniform
Winter

Soil Tolerances

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Soil drainage

  • free

Soil texture

  • heavy
  • light
  • medium

Special soil tolerances

  • infertile

Notes on Natural Enemies

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Ustilago tragana and Striga densiflora have been reported on T. racemosus (Srinivasan, 1947; Ramakrishnan and Srinivasan, 1950).

Means of Movement and Dispersal

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Natural Dispersal

Although the seeds of T. racemosus have hooked spines adapted for animal dispersal, Catasús Guerra (2015) also reports the species as being wind dispersed.

Vector Transmission (Biotic)

Tragus racemosus seeds have hooked spines adapted for animal dispersal (Freund et al., 2014; Catasús Guerra, 2015; Shabana et al., 2018; PROTA, 2020).

Accidental Introduction

Tragus racemosus has been accidentally introduced to various countries as a contaminant of wool products and waste (Parlin, 1904; Alien plants of Belgium, 2020SEINet, 2020). It is also reported as introduced in ship ballast (Angelo and Boufford, 1998; Native Plant Trust, 2020).

Pathway Causes

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CauseNotesLong DistanceLocalReferences
DisturbanceFound growing in open disturbed areas Yes PROTA (2020)
ForageOccasionally foraged by animals Yes PROTA (2020)
Harvesting fur, wool or hairAccidentally introduced to various countries as a contaminant of wool products Yes Yes Alien plants of Belgium (2020); SEINet (2020)
HitchhikerAccidentally introduced to various countries as a contaminant of wool products Yes Yes Alien plants of Belgium (2020); SEINet (2020)
Off-site preservation Germplasm collections are available at USDA facilities and at the Millennium Seed Bank Yes Yes Kew Royal Botanic Gardens (2020); USDA-ARS (2020)

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Clothing, footwear and possessionsNo information available but possible as the seeds have hooked spines that could attach easily to clothes and footwear Yes PROTA (2020)
Debris and waste associated with human activitiesFound growing at dump sites near wool factories and ballast dump sites Yes Yes Native Plant Trust (2020)
GermplasmGermplasm collections are available at USDA facilities and at the Millennium Seed Bank Yes Yes Kew Royal Botanic Gardens (2020); USDA-ARS (2020)
Ship ballast water and sedimentFound growing at ballast dump sites Yes Yes Native Plant Trust (2020)
Soil, sand and gravelPossible. No information available but as it is an ephemeral species, the seeds that germinate in the summer are at least from the previous season Yes
WindAlthough adapted for animal dispersal, there is a report of the species being wind dispersed Yes Catasús Guerra (2015)

Impact Summary

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CategoryImpact
Economic/livelihood Negative
Environment (generally) Positive and negative

Economic Impact

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Tragus racemosus is reported as causing severe 'seedy wool' problems on sheep farms in Africa and as a potential seed contaminant, but without further details given (PROTA, 2020). In France, in the Haute Provence region, this species is regarded as a weed, and reported as aggressively carpeting lavender fields during summer after they have been cleared of weeds in early summer (Bogaard et al., 2020). Although predicted to have low competitive ability and not an important weed in the organic arable fields of Provence, T. racemosus is considered an effective, and increasing, summer-annual colonist of fallow sites where existing annual vegetation has been removed in spring or early summer (Bogaard et al., 2020).

Impact: Biodiversity

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There are no details about the impact of T. racemosus on other species; according to Catasús Guerra (2015) it can outcompete other species in dry and nutrient-poor habitats.

Risk and Impact Factors

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Invasiveness
  • Proved invasive outside its native range
  • Has a broad native range
  • Pioneering in disturbed areas
  • Fast growing
  • Has propagules that can remain viable for more than one year
Impact outcomes
  • Damages animal/plant products
Impact mechanisms
  • Competition - monopolizing resources
  • Rapid growth
  • Produces spines, thorns or burrs
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally

Uses

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Social Benefit

Tragus racemosus is occasionally grazed by sheep, cattle and camels (Ali et al., 2009; PROTA, 2020); due to its short cycle and low seed yield, it is not actively used for forage. The seeds are listed as used in porridges but without further details (PROTA, 2020).

Environmental Services

The presence of T. racemosus is generally indicative of a denuded field in an early successional stage (PROTA, 2020). It may be used as a cover crop to prevent soil erosion (Bogaard et al., 2020).

Uses List

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Animal feed, fodder, forage

  • Fodder/animal feed

Environmental

  • Erosion control or dune stabilization

Human food and beverage

  • Seeds

Similarities to Other Species/Conditions

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According to Anton (1981), nearly all the species of Tragus at one time or another have been confused with T. racemosus although the species is well delimited by the 7-nerved second glume and the clustered arrangement of the spikelets. Sometimes only (3-)5 nerves in the second glume are strongly developed, producing spines that are almost contiguous to one another, with 2-4 intermedial nerves being less evident and diminishing towards the apex.

Tragus racemosus is distinguished from T. berteronianus by its looser inflorescence, especially towards the bottom, with larger spikelets (3-4 mm). T. berteronianus has a tight, cylindrical inflorescence with smaller (2-3 mm) spikelets (SEINet, 2020).

References

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Ali, I., Chaudhry, M. S., Farooq, U., 2009. Camel rearing in Cholistan desert of Pakistan. Pakistan Veterinary Journal, 29(2), 85-92. http://www.pvj.com.pk/

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Knowlton, CH, Blake, SF, Cushman, JA, Deane, W, 1913. Reports on the flora of the Boston district, - XVI. Rhodora, 15(171), 54-59.

Lawesson, JE, 1990. Sahelian woody vegetation in Sénégal. Vegetatio, 86(2), 161-174.

Leistner, O. A., Werger, M. J. A. , 1973. Southern Kalahari phytosociology. Vegetatio, 28(5), 353-399.

Missouri Botanical Garden, 2020. Tropicos database. In: Tropicos database St. Louis, Missouri, USA: Missouri Botanical Garden.http://www.tropicos.org/

Moore, G., Brecht, R., Schweitzer, D., 2016. Additions and corrections to the checklist of vascular plants of Cumberland County, New Jersey. Bartonia, 68, 1-59.

Native Plant Trust, 2020. Native Plant Trust – Go Botany. Framingham, Massachusetts, USA: Native Plant Trust.https://gobotany.nativeplanttrust.org/

Obeid, M., Mahmoud, A., 1969. The vegetation of Khartoum Province. Sudan Notes and Records, 50, 134-159.

Palmer, A. R., 1991. Vegetation/environment relationships in the central area of the Cape midlands, South Africa. Coenoses, 6, 29-38.

Parlin, JC, 1904. Some casual elements in the flora of western Maine. Rhodora, 6(65), 81-84.

Pohl, RW, 1947. A taxonomic study on the grasses of Pennsylvania. The American Midland Naturalist, 38(3), 513-604.

Proctor, GR, 1982. More Additions to the Flora of Jamaica. In: Journal of the Arnold Arboretum , 63(3) . 199-316.

PROTA, 2020. PROTA4U web database. In: PROTA4U web database Wageningen and Nairobi, Kenya, Netherlands\Nairobi: Plant Resources of Tropical Africa.https://www.prota4u.org/database/

Ramakrishnan, T. S. , Srinivasan, K. V. , 1950. Two grass smuts. Current Science, 19(7), 216-217 pp.

Reed, CF, 1954. New or additional records of grasses in Maryland and Delaware. In: Rhodora , 56(668) . 178-181.

SEINet, 2020. Southwest Environmental Information Network SEINet - Arizona - New Mexico Chapter. USA: Southwest Environmental Information Network (SEINet).https://swbiodiversity.org/seinet/index.php

Shabana, H. A., Navarro, T., El-Keblawy, A., 2018. Dispersal traits in the hyper-arid hot desert of the United Arab Emirates. Plant Ecology and Evolution, 151(2), 194-208. doi: 10.5091/plecevo.2018.1359

Srinivasan, A. R., 1947. Some new hosts for Striga. Current Science, 16, 320-1.

Sulekic, A, Zapater, MA, 2001. (El género Tragus (Poaceae, Zoisieae) en la Argentina). Darwiniana, 39(3-4), 247-254.

USDA-ARS, 2020. 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

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

Distribution References

Ali I, Chaudhry M S, Farooq U, 2009. Camel rearing in Cholistan desert of Pakistan. Pakistan Veterinary Journal. 29 (2), 85-92. http://www.pvj.com.pk/

Alien plants of Belgium, 2020. Manual of the alien plants of Belgium. In: Manual of the alien plants of Belgium, Belgium: National Botanic Garden of Belgium. http://alienplantsbelgium.be/

Catasús Guerra L, 2015. Considerations about the invasive grasses in Cuba. (Consideraciones sobre las gramíneas invasoras en Cuba). In: Revista del Jardín Botánico Nacional, 36 115-150.

El-Gadi A , Sherif AS , El-Taife, Labani RM, 1987. New plant records for Libya - II. Willdenowia. 16 (2), 409-413.

Euro+Med, 2020. Euro+Med PlantBase - the information resource for Euro-Mediterranean plant diversity. In: Euro+Med PlantBase - the information resource for Euro-Mediterranean plant diversity, http://ww2.bgbm.org/EuroPlusMed

Fasseaux W, 1949. (Les Tragus adventices en Belgique). Bulletin de la Société Royale de Botanique de Belgique/Bulletin van de Koninklijke Belgische Botanische Vereniging. 82 (1), 67-70.

Flora of Pakistan, 2020. Flora of Pakistan/Pakistan Plant Database (PPD). Tropicos website. In: Flora of Pakistan/Pakistan Plant Database (PPD). Tropicos website, St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria. http://www.tropicos.org/Project/Pakistan

Hanelt P, 2020. Mansfeld's World Database of Agricultural and Horticultural Crops. In: Mansfeld's World Database of Agricultural and Horticultural Crops, Gatersleben, Germany: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK). http://mansfeld.ipk-gatersleben.de/apex/f?p=185:3:0::NO

Harsh L N, Sen D N, 1975. Net above-ground biomass and production in the monsoonal vegetation at Jodhpur, Rajasthan, India. Folia Geobotanica et Phytotaxonomica. 10 (2), 211-215.

India Biodiversity Portal, 2020. Online Portal of India Biodiversity. In: Online Portal of India Biodiversity, http://indiabiodiversity.org/species/list

Knowlton CH, Blake SF, Cushman JA, Deane W, 1913. Reports on the flora of the Boston district, - XVI. Rhodora. 15 (171), 54-59.

Lawesson JE, 1990. Sahelian woody vegetation in Sénégal. Vegetatio. 86 (2), 161-174.

Lazkov G, Sennikov A, 2014. New records in vascular plants alien to Kyrgyzstan. Biodiversity Data Journal. e1018.

Little E L Jr, Campbell R S, 1943. Flora of Jornada Experimental Range, New Mexico. American Midland Naturalist. 626-70. DOI:10.2307/2421206

Lyubinska L G, 2009. Alien plants of the Podilski Tovtry National Nature Park (Ukraine). Biodiversity: Research and Conservation. 53-64. DOI:10.2478/v10119-009-0019-x

Missouri Botanical Garden, 2020. Tropicos database. In: Tropicos database, St. Louis, Missouri, USA: Missouri Botanical Garden. http://www.tropicos.org/

NOBANIS, 2020. North European and Baltic Network on Invasive Alien Species. In: North European and Baltic Network on Invasive Alien Species, http://www.nobanis.org/

Online Atlas of the British & Irish Flora, 2020. Online Atlas of the British & Irish Flora. In: Online Atlas of the British & Irish Flora, Botanical Society of the British Isles; Biological Records Centre; Joint Nature Conservation Committee; Centre for Ecology and Hydrology. http://www.brc.ac.uk/plantatlas/

Parlin JC, 1904. Some casual elements in the flora of western Maine. Rhodora. 6 (65), 81-84.

Pohl RW, 1947. A taxonomic study on the grasses of Pennsylvania. The American Midland Naturalist. 38 (3), 513-604.

Proctor GR, 1982. More Additions to the Flora of Jamaica. In: Journal of the Arnold Arboretum, 63 (3) 199-316.

PROTA, 2020. PROTA4U web database. In: PROTA4U web database, Wageningen and Nairobi, Kenya, Netherlands\Nairobi: Plant Resources of Tropical Africa. https://www.prota4u.org/database/

Rat M, Simonović P, Glavendekić M, Paunovic M, Stojanović V, Karaman M, Radišić D, Anačkov G, 2016. Country reports. Overview of the invasive alien species in Serbia. In: ESENIAS Scientific Reports 1. State of the art of alien species in south-eastern Europe. [ed. by Rat M, Trichkova T, Scalera R, Tomov R, Uludag A]. Novi Sad, Serbia: University of Novi Sad, IBER-BAS, ESENIAS. 91-114.

Reed CF, 1954. New or additional records of grasses in Maryland and Delaware. In: Rhodora, 56 (668) 178-181.

Seebens H, Blackburn T M, Dyer E E, Genovesi P, Hulme P E, Jeschke J M, Pagad S, Pyšek P, Winter M, Arianoutsou M, Bacher S, Blasius B, Brundu G, Capinha C, Celesti-Grapow L, Dawson W, Dullinger S, Fuentes N, Jäger H, Kartesz J, Kenis M, Kreft H, Kühn I, Lenzner B, Liebhold A, Mosena A (et al), 2017. No saturation in the accumulation of alien species worldwide. Nature Communications. 8 (2), 14435. http://www.nature.com/articles/ncomms14435

SEINet, 2020. Southwest Environmental Information Network SEINet - Arizona - New Mexico Chapter., USA: Southwest Environmental Information Network (SEINet). https://swbiodiversity.org/seinet/index.php

Sulekic A, Zapater MA, 2001. (El género Tragus (Poaceae, Zoisieae) en la Argentina). Darwiniana. 39 (3-4), 247-254.

Terrell EE, Peterson PM, 2009. Annotated list of Maryland grasses (Poaceae). Journal of the Botanical Research Institute of Texas. 3 (2), 905-919.

USDA-ARS, 2020. 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

USDA-NRCS, 2020. The PLANTS Database. In: The PLANTS Database, Greensboro, North Carolina, USA: National Plant Data Team. https://plants.sc.egov.usda.gov

Links to Websites

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WebsiteURLComment
E-Flora of South Africahttps://www.sanbi.org/biodiversity/foundations/biosystematics-collections/e-flora/
Euro+Med PlantBasehttp://ww2.bgbm.org/EuroPlusMed
Flora of Pakistanhttp://www.tropicos.org/Project/Pakistan
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.
Global register of Introduced and Invasive species (GRIIS)http://griis.org/Data source for updated system data added to species habitat list.
India Biodiversity Portalhttp://indiabiodiversity.org/species/list
Millennium Seed Bank - Seed Listhttp://apps.kew.org/seedlist/SeedlistServlet
Native Plant Trusthttps://gobotany.nativeplanttrust.org
PROTA4U web databasehttps://www.prota4u.org/database/
SEINet data portalhttps://swbiodiversity.org/seinet/index.php

Contributors

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30/04/2020 Original text by:

Jeanine Vélez Gavilán, University of Puerto Rico at Mayagüez, Puerto Rico

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