Dune Sandspur

Cenchrus tribuloides L.

Cenchrus tribuloides
Stephen M. Young

Monocotyledoneae (Monocots)
Poaceae (Grass Family)
State Protection
Listed as Threatened by New York State: likely to become Endangered in the foreseeable future. For animals, taking, importation, transportation, or possession is prohibited, except under license or permit. For plants, removal or damage without the consent of the landowner is prohibited.
Federal Protection
Not Listed
State Conservation Status Rank
Imperiled in New York - Very vulnerable to disappearing from New York due to rarity or other factors; typically 6 to 20 populations or locations in New York, very few individuals, very restricted range, few remaining acres (or miles of stream), and/or steep declines.
Global Conservation Status Rank
Secure globally - Common in the world; widespread and abundant (but may be rare in some parts of its range).


Did you know?

The species name of this spiny-fruited grass derives from the Latin "tribulus", the name for the antipersonnel weapon called a caltrop. This weapon usually consists of four spikes, one of which always points upward when supported on the ground by the other three (Wikipedia contributors). While the Civil War raged on in 1862 William H. Leggett collected New York's first specimen of this species on Staten Island. The specimen is now in the collection of the New York Botanical Garden.

State Ranking Justification

There are 8 known populations, but almost all of them have 100 plants or less. They need disturbed sands to thrive, but they are also subject to direct destruction by beachgoers, especially since they occur on popular tourist beaches. There are about 20 historical occurrences.

Short-term Trends

The short-term trend seems stable with little fluctuation over the years. Populations would have been expected to grow with more protection of the beach for rare shorebirds, but this does not seem to have happened.

Long-term Trends

The number of populations has declined over the years and the number of beaches available to the species is not expected to increase.

Conservation and Management


The beaches are heavily used and the plants are subject to beach grooming, ATV use, trampling, and succession.

Conservation Strategies and Management Practices

Protect the beach habitat from direct destruction by human means, but disturb areas enough so open sands prevail.

Research Needs

Research on habitat preference is needed to determine why this plant prefers one part of the beach over another.



In New York, dune sandspur is known from maritime sand dunes and beaches (New York Natural Heritage Program 2010). Coastal sands, especially on dunes (Gleason and Cronquist 1991). Moist, sandy dunes (Utah State University 2005).

Associated Ecological Communities

  • Maritime beach (guide)
    A community with extremely sparse vegetation that occurs on unstable sand, gravel, or cobble ocean shores above mean high tide, where the shore is modified by storm waves and wind erosion.
  • Maritime dunes (guide)
    A community dominated by grasses and low shrubs that occurs on active and stabilized dunes along the Atlantic coast. The composition and structure of the vegetation is variable depending on stability of the dunes, amounts of sand deposition and erosion, and distance from the ocean.
  • Maritime grassland* (guide)
    A grassland community that occurs on rolling outwash plains of the glaciated portion of the Atlantic coastal plain, near the ocean and within the influence of offshore winds and salt spray.

* probable association but not confirmed.

Associated Species

  • Ammophila breviligulata (beach grass)


New York State Distribution

This grass is most common on the south shore beaches of western Long Island and on the eastern shore of Staten Island. There is one specimen from the late 1800s from the Albany area.

Global Distribution

Cenchrus tribuloides occurs mainly along the coastal plain, from Long Island south to Florida and west along the Gulf Coast to Louisiana. There are a few scattered inland populations from Maine to Ohio, Virginia, and Georgia.

Identification Comments

General Description

Dune Sandspur is a stout, annual grass species. The stems are trailing or decumbent, and up to 1 meter long, with short (up to 14 cm), wide (to 14 mm) leaves and soft-hairy leaf sheaths. There is a single spikelet (occasionally 2) enclosed in a densely hairy bur with from 15 to 40 barbed spines (treacherous to the barefoot), each from 4 to 8 mm long (Gleason and Cronquist 1991).

Best Life Stage for Proper Identification

Dune sandspur may be identified vegetatively, though fruits are best for quick identification. Barefoot dune explorations may result in an unintended, painful discovery of this species.

Similar Species

Cenchrus is our only genus of grass with spiny burs. C. longispinus, our other native sandspur in New York, is much more widespread than C. tribuloides. It has less hairy spikelets with more (45 to 75) spines per bur, and has 2 to 3 spikelets per bur.

Best Time to See

Dune sandspur may be seen from June through October.

  • Flowering
  • Fruiting

The time of year you would expect to find Dune Sandspur flowering and fruiting in New York.

Dune Sandspur Images


Dune Sandspur
Cenchrus tribuloides L.

  • Kingdom Plantae
    • Phylum Anthophyta
      • Class Monocotyledoneae (Monocots)
        • Order Cyperales
          • Family Poaceae (Grass Family)

Additional Common Names

  • Sandspur

Additional Resources

Best Identification Reference

Flora of North America Editorial Committee. 2003. Flora of North America, North of Mexico. Volume 25. Magnoliophyta: Commelinidae (in part): Poaceae, part 2. Oxford University Press, New York. 783 pp.

Other References

Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.

Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.

Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.

New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.

New York Natural Heritage Program. 2024. New York Natural Heritage Program Databases. Albany, NY.

Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York


About This Guide

This guide was authored by: Stephen M. Young, Richard M. Ring.

Information for this guide was last updated on: February 23, 2011

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Cenchrus tribuloides. Available from: https://guides.nynhp.org/dune-sandspur/. Accessed June 23, 2024.