Fact Sheets


Tribulus terrestris L.

Family :

Famille :


Synonym(s) :

Synonyme(s) :

Tribulus terrestris L. var. terrestris (USDA-ARS 2022)


Common Name(s) :

Nom(s) commun(s) :

Puncture vine
(English) (GC 2016)

Croix-de-Malte (French) (GC 2016)

Caltrop (English) (USDA-ARS 2022; CABI 2022)

Dacn-ash-sheikh (Arabic) (CABI 2022)

Abrolhos (Portuguese) (CABI 2022)

Abrojo terrestre (Spanish) (CABI 2022)

  • Puncture vine (Tribulus terrestris) nutlets

  • Puncture vine (Tribulus terrestris) nutlets

  • Puncture vine (Tribulus terrestris) nutlet

  • Puncture vine (Tribulus terrestris) nutlet

  • Puncture vine (Tribulus terrestris) seed

  • Puncture vine (Tribulus terrestris) nutlet, cross-section

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Regulation :

Remarques Réglementation:

  • CFIA Weed Seeds Order - Class 2: Primary Noxious Weed Seeds
  • USA Federal Noxious Weed Seed List

Regulation Notes:

Distribution :

Répartition :

Exact native range obscure, possibly native to Africa, Europe, temperate Asia and Australia (USDA-ARS 2022). Introduced in North and South America (CABI 2022). Found throughout the United States with the exception of a few states in the eastern and northeastern regions (Kartesz 2015). Occurs in British Columbia and Ontario (Brouillet et al. 2010+).

Habitat and Crop Association :

Habitat et Cultures Associées :

Cultivated fields, pastures, gardens, orchards, vineyards, roadsides and disturbed areas, especially with dry and sandy soils (Holm et al. 1991; Darbyshire 2003). A weed of many crops including: Gossypium hirsutum (cotton), Zea mays (corn), Medicago sativa (alfalfa), Trifolium spp. (clover), Sorghum bicolor (sorghum), Arachis hypogaea (peanuts), Beta vulgaris subsp. vulgaris (sugar beets), vineyards fruits, and vegetables in many countries around the world (Holm et al. 1991).

Economic Use, cultivation area, and Weed Association :

Utilisation économique, zone de culture et association de mauvaises herbes :

Duration of Life Cycle :

Durée du cycle vital:


Dispersal Unit Type :

Type d’unité de dispersion :

Schizocarp, divided into 5 (sometimes 4) mericarps (Walters 2011)

General Information


The spines on Tribulus terrestris mericarps are aligned so that at least one spine is pointing upwards and can be dispersed by attaching to livestock, people, farm machinery, and automobile tires (Holm et al. 1991). T. terrestris is believed to have moved outside its native range in sheep’s wool. It is also dispersed by water and as a contaminant in hay, straw, manure, sand, gravel, and within dried fruit (Holm et al. 1991; Scott and Morrison 1996).

T. terrestris plants have been observed to produce 400 mericarps per m2 (Holm et al. 1991) and 1000 mericarps in a single plant under optimal growth conditions (Scott and Morrison 1996). Seeds remain in the mericarp after maturity, and germinate through the mericarp wall (Holm et al. 1991). Seeds can remain viable for several years in the soil (Scott and Morrison 1996).

The spines on the mericarps can injure livestock, both externally and internally if ingested (Holm et al. 1991). The plant is poisonous to livestock, especially sheep, where it can cause damage to the liver (Holm et al. 1991).



Tribulus terrestris burs stuck on bottom of shoe (Eric Coombs, Oregon Department of Agriculture, Bugwood.org)



  • Schizocarp


    • Schizocarp diameter is 10 – 15 mm (excluding spines) (FNA 1993+); 5 – 10 mm (Walters 2011)


    • Schizocarp is globose in shape and has five angles (Walters 2011)

    Surface Texture

    • Schizocarp is woody, spiny with scattered hairs (Walters 2011)


    • Schizocarp is greenish-brown to yellowish-brown in colour

    Other Features

    • Schizocarp is comprised of 4 or 5 mericarps (Walters 2011)
    • Schizocarp breaks into individual mericarps when mature
  • Mericarp


    • Mericarp length*: 3.2 – 7.2 mm; width: 2.1 – 3.3 mm
    *Note: minimum and maximum of 10 mericarps in a normal range of this species using image measurement (ISMA 2020)


    • Mericarp is wedge-shaped with straight sides, three-angled in edge view

    Surface Texture

    • Mericarp has a thick, woody wall
    • Mericarp has a ridged reticulation pattern with large interspaces and spiny tubercles where the ridges meet
    • Mericarp surface generally have scattered, long hairs that may be removed during processing


    • Mature mericarps are dull straw yellow, greyish-yellow, or greenish-brown
    • Immature mericarps are shiny green coloured

    Other Features

    • Mericarp does not split open at maturity (Holm et al. 1991)
    • Mericarps generally have one pair of long spines near one end 3 – 7 mm long, some may have a smaller pair near the opposite end (FNA 1993+)
    • Each mericarp may have 2-4 seeds (Holm et al 1991; Scott and Morrison 1996) and sometimes 5 (Walters 2011)
  • Seed


    • Seed length: 3.5 – 4.0 mm (Semerdjieva et al. 2011)


    • Seed contained in the mericarp is cylindrical with a pointed long tip, slightly compressed in edge view (Holm et al. 1991; Semerdjieva et al. 2011)

    Surface Texture

    • Seed surface is smooth with longitudinal wrinkles (Semerdjieva et al. 2011)


    • Seed colour is dull light yellow or pinkish-yellow

    Other Features

    Hilum and Hilum area

    • Hilum is not visible on the seed
  • Embryo


    • Embryo partially fills the seed


    • Embryo is spatulate (Shojaii et al. 2018)


    • Endosperm is soft and oily

    Other Features

    • Embryo is in axial position (Shojaii et al. 2018)

Identification Tips


Mericarps of Tribulus species are recognizable by their thick, woody texture, three-angled shape and paired spines or wings. Tribulus terrestris is the most widespread species, the mericarps are wedge-shaped with long spines and bristles coming from spiny tubercles. The next most common species, T. cistoides, has oval-shaped mericarps with generally shorter spines that are densely hairy. Species of Tribulus, such as T. macrocarpus and T. pentandrus have longitudinal wings rather than spines.

Additional Botany Information



  • Flowers are comprised of five yellow petals and are 7 – 15 mm in diameter (CABI 2022)

Vegetative Features

  • Stems are prostrate and may be green or reddish (FNA 1993+); however, plants growing in shady locations may be more erect (CABI 2022)
  • Compound leaves have opposite leaf arrangement and are comprised of three to eight pairs of opposite leaflets (CABI 2022)

Similar Species


Similar species are based on a study of seed morphology of various species, and those with similar dispersal units are identified. The study is limited by physical specimen and literature availability at the time of examination, and possibly impacted by the subjectivity of the authors based on their knowledge and experience. Providing similar species information for seed identification is to make users aware of similarities that could possibly result in misidentification.

Tribulus cistoides L.

T. cistoides has a perennial habit, found in coastal areas (Holm et al. 1991), the edges of the mericarp curved, densely hairy and the 2 spines may be longer (5 – 7 mm, FNA 1993+) , compared to the annual T. terrestris with straight edges, sparsely bristly mericarps and the spines range from 3 -7 mm (FNA 1993+).

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Brouillet, L., Coursol, F., Meades, S. J., Favreau, M., Anions, M., Bélisle, P. and Desmet, P. 2010+. VASCAN, the database of vascular plants of Canada. http://data.canadensys.net/vascan/ Accessed March 03, 2022.

Centre for Agriculture and Bioscience International (CABI). 2022. Invasive Species Compendium, CAB International, Wallingford, UK. https://www.cabidigitallibrary.org/journal/cabicompendium Accessed March 03, 2022.

Darbyshire, S. J. 2003. Inventory of Canadian Agricultural Weeds. Agriculture and Agri-Food Canada, Research Branch. Ottawa, ON.

Flora of North America (FNA) Editorial Committee, eds. 1993+. Flora of North America North of Mexico [Online]. 22+ vols. New York and Oxford.  Accessed December 29, 2022.

Global Biodiversity Information Facility (GBIF) Secretariat. 2022. https://doi.org/10.15468/39omei Accessed via https://www.gbif.org/species/5421116 Accessed December 29, 2022.

Government of Canada (GC). 2016. Canadian Weed Seeds Order. https://laws-lois.justice.gc.ca/eng/regulations/SOR-2016-93/page-2.html (English) https://laws-lois.justice.gc.ca/fra/reglements/DORS-2016-93/page-2.html (French)

Holm, L.G., Plucknett, D.L., Pancho, J.V. and Herberger, J.P. 1991. The World’s Worst Weeds: Distribution and Biology. Krieger Publishing Company, Florida. 609 pp.

International Seed Morphology Association (ISMA). 2020. Method for Seed Size Measurement. Version 1.0. ISMA Publication Guide.

Kartesz, J. T. 2015. The Biota of North America Program (BONAP). North American Plant Atlas. Chapel Hill, N.C., www.bonap.org/MapSwitchboard.html Accessed March 03, 2022.

Scott, J.K and Morrison, S. 1996. Variation in Populations of Tribulus terrestris (Zygophyllaceae). 1. Burr Morphology. Australian Journal of Botany 44: 175-190.

Semerdjieva, I., Yankova-Tsvetkova,E., Baldjiev, G. and Yurukova-Grancharova, P. 2011. Pollen and Seed Morphology of Tribulus terrestris L. (Zygophyllaceae). Biotechnology & Biotechnological Equipment, 25: 2379-2382.

Shojaii, F.M., Aliasgarpoor, M. ,Kazemi, E.M. 2018. Histological study of embryo formation in Tribulus terrestris from harmal spin. Ukrainian Journal of Ecology, 8: 261-272.

U.S. Department of Agriculture-Agricultural Research Services (USDA-ARS). 2022. Germplasm Resources Information Network (GRIN), https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysimple.aspx Accessed March 03, 2022.

Walters, D.S. 2011. Identification Tool to Weed Disseminules of California Central Valley Table Grape Production Areas.

USDA APHIS PPQ CPHST Identification Technology Program, Fort Collins, CO. http://idtools.org/id/table_grape/weed-tool/ Accessed February 17, 2022.



Jennifer Neudorf, Angela Salzl, Ruojing Wang, Karen Castro, Katrina Entwistle
Canadian Food Inspection Agency