BugwoodWiki Article

spiny cocklebur
Xanthium spinosum L.

Overview

Appearance
Xanthium spinosum is an erect, rigid, much-branched annual herb, 11.8-39.4 in. (30-100 cm) tall and up to 59.1 in. (150 cm) or more wide. Stems are striate, yellowish or brownish gray, and finely pubescent.
Foliage
Leaves are lanceolate, entire, toothed or lobed, 1.2-3.1 in. (3-8 cm) long, 0.24-1.02 in. (6-26 mm) wide, glabrous or strigose above, and silvery-tomentulose beneath. They are dull gray-green above with a conspicuous white midrib and short petioles 0.4 in. (1 cm). Each leaf base is armed at the axil with yellow three-pronged spines 0.8-2 in. (2-5 cm) long, often opposite in pairs.
Flowers
The monoecious flowers may be solitary or found in axillary clusters. Greenish flowers are inconspicuous.
Fruit
Fruits are yellowish egg shaped burs covered with hooked glabrous spines. Each fruit contains two seeds.
Ecological Threat
Xanthium spinosum is a serious weed in many agricultural crops and in animal production. Seeds are easily spread, due to their ability to float and to "hitchhike" on humans and animals. The plants can quickly become dominant in an area due to prolific seed production and high germination and survival rates. It invades pastures and grazing lands, reducing forage production. Xanthium species are toxic to most domestic animals, particularly swine and horses.

General Description

The following description of Xanthium spinosum is adapted from Abrams (1940), Jepson (1951), Munz and Keck (1973), Robbins et al. (1970), and Holm et al. (1977).

Xanthium spinosum is an erect, rigid, much-branched annual herb, 3-10 dm tall and up to 15 dm or more wide. Stems are striate, yellowish or brownish gray, and finely pubescent. The cotyledons are linear-lanceolate in shape, differing in appearance from later developing leaves. True leaves are lanceolate, entire, toothed or lobed, 3-8 cm long, 6-26 mm wide, glabrous or strigose above, and silvery-tomentulose beneath. They are dull gray-green above with a conspicuous white midrib and short petioles (1 cm). Each leaf base is armed at the axil with yellow three-pronged spines 2-5 cm long, often opposite in pairs.

Flower heads are in axillary clusters or often solitary. Flowers are inconspicuous, greenish, and monoecious; male flowers in almost globular heads in axils of upper most leaves, and female flowers in axils of lower leaves, developing into a bur. The bur is two--celled, oblong, nearly egg-shaped, slightly flattened, 10-13 mm long, 4 mm wide, pale yellowish, more or less striate, glandular, covered with slender, hooked, glabrous spines from more or less thickened bases, with the two apical beaks short and straight. Each bur contains two flattened, thick-coated, dark brown or black seeds, the lower germinating first.

Xanthium is derived from the Greek, xanthos, meaning "yellow" and is thought to refer to a yellow dye obtainable from some species.

Unlike cocklebur (X. strumarium), spiny clotbur has conspicuous narrower leaves tapering at both ends, short petioles, conspicuous three-pronged spines at the leaf base, and egg-shaped burs covered with hooked, thorny prickles.

Resources

Selected Images


5374593
5374593

spiny cocklebur
Xanthium spinosum
Plant(s)
Joseph M. DiTomaso
5391790
5391790

spiny cocklebur
Xanthium spinosum
Plant(s)
Barry Rice
5392709
5392709

spiny cocklebur
Xanthium spinosum
Stem(s)
John M. Randall
5392710
5392710

spiny cocklebur
Xanthium spinosum
Foliage
John M. Randall
5399844
5399844

spiny cocklebur
Xanthium spinosum
Plant(s)
Robert Vidéki
5461332
5461332

spiny cocklebur
Xanthium spinosum
Fruit(s)
D. Walters and C. Southwick
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5461334

spiny cocklebur
Xanthium spinosum
Fruit(s)
D. Walters and C. Southwick
5461335
5461335

spiny cocklebur
Xanthium spinosum
Fruit(s)
D. Walters and C. Southwick

Maps


EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

EDDMapS Distribution

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit Invasive.org

State Regulated List

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Asteridae
Order: Asterales
Family: Asteraceae
Genus: Xanthium

Other System Links

Plants: XASP2
Bayer: XANSP
GRIN: 42071
ITIS: 38691
NPDN Pest: PBFDQBF

Synonyms and Other Names

Other Common Names:
spiny cockleburr, Bathurst burr, cocklebur, spiny cocklebur, spiny colklebur, spanish-thistle, daggerweed, spiny burweed, thorny burweed

Categories

Category: Forbs/Herbs