Ontario Weeds: Long-spined sandbur

Table of Contents

1. Name
2. Other Names
3. Family
4. General Description
   • Photos and Pictures
5. Stems and Roots
6. Flowers and Fruit
7. Habitat
8. Similar Species
9. Related Links

Name: Long-spined sandbur, Cenchrus longispinus (Hack.) Fern.,

Other Names: cenchrus épineux, Bur grass

Family: Grass Family (Gramineae)

General Description: Annual, reproducing only by seed.

Photos and Pictures

Long-spined sandbur

Long-spined sandbur

Long-spined sandbur. A. Plant. B. Leaf-base. C. Bur enclosing spikelet.

Stems & Roots: Stems mostly 10-60cm (4-24in.) long, erect or spreading or lying on the ground; leaves flat or margins inrolled, usually constricted and partially twisted at the junction with the leaf sheaths, 2-12cm (1-5in.) long, mostly hairless but rough in one direction; leaf sheaths split with overlapping margins these margins on young plants membranous and without hair, but on upper leaf sheaths of older stems membranous and usually also with few to many hairs 1-2mm (1/25-1/12in.) long; ligule a fringe of hair mostly less than 1mm (1/25in.) long; there is also a tuft of short and long (2-3mm, 1/12-1/8in.) hair on each side of the collar at the junction between blade and sheath; no auricles.

Flowers & Fruit: Inflorescence a group of spiny burs at the end of each stem; each bur 4-6mm (1/6-¼in.) long, containing 1 or 2 "seeds," and covered with extremely sharp spines 2-6mm (1/12-¼in.) long with backward-pointing barbs which anchor into skin, etc., the whole bur breaking off when mature. Flowers from August to September.

Habitat: Long-spined sandbur is a native grass in areas of sandy soil throughout southern Ontario. Though normally found along sandy beaches, sand dunes, riverbanks and roadsides, it is becoming a problem in tobacco fields, other row crops and occasionally in lawns and gardens on sandy soils.

Similar Species: Once the burs have emerged, Long-spined sandbur cannot be confused with any other grass in Ontario. Younger plants can be distinguished from most other grasses by the split sheath with membranous margins, and usually some hair on the margin, together with the hairy ligule and the tufts of long hair on either side at the junction between blade and sheath.

Related Links

... on general Weed topics
... on weed identification, order OMAFRA Publication 505: Ontario Weeds
... on weed control, order OMAFRA Publication 75: Guide To Weed Control

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