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Native Plant Trust: Go Botany Discover thousands of New England plants

Xanthium strumarium — rough cocklebur

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Facts

The fruits of rough cocklebur cling to animal fur and human clothing for dispersal. Livestock producers consider the species a nuisance because it does get in the hides of farm animals. The seeds and cotelydons are also somewhat poisonous to livestock.

Habitat

Anthropogenic (man-made or disturbed habitats), brackish or salt marshes and flats, coastal beaches (sea beaches), dunes, marshes, shores of rivers or lakes, wetland margins (edges of wetlands)

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
  • terrestrial
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf type
leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
Leaf arrangement
alternate: there is one leaf per node along the stem
Leaf blade edges
  • the edge of the leaf blade has lobes, or it has both teeth and lobes
  • the edge of the leaf blade has teeth
Flower type in flower heads
the flower head has disk flowers only, and lacks the strap-shaped flowers
Ray flower color
NA
Tuft or plume on fruit
there is no plume, or the plume is made up of scales, awns, a crown, or a rim
Spines on plant
the plant has no spines
Leaf blade length
40–180 mm
Disk flower number
21-50
Show all characteristics

  • Flowers

    Bases of bract appendages
    NA
    Bract cycle number
    • there are three or more cycles of bracts
    • there are two main cycles of bracts
    • there is one main cycle of bracts
    Bract outer side hair type
    the bracts are hairy, with simple hairs on their outer surface
    Bract outer side hairs
    the bracts are hairy on their outer surfaces
    Bract separation
    • at least some flower heads have bracts connected to one another at or near their bases
    • the bracts appear completely unconnected to one another on all flower heads
    Bract spines
    the bracts have no spines
    Disk flower color
    • green to brown
    • white
    Disk flower lobe number
    5
    Disk flower number
    21-50
    Disk flower reproductive parts
    the disk flower has either only pollen- or only seed-producing parts
    Disk flower shape
    the disk flower is tube-shaped (cylindrical), or gradually widening like a funnel
    Flower head number
    • each flowering stem has four or more flower heads on it
    • each flowering stem has only one to three flower heads on it
    Flower head outer flowers
    at the outer edge of the flower head, the flowers have no enlarged lobe or strap, and are of similar size as those in the center of the disk
    Flower head platform
    the base has papery scales on it
    Flower head platform surface
    the scales are slightly hairy, at least near the top
    Flower head position
    some or all the flower heads are grouped in clusters of two or more
    Flower head profile
    the disk is conical across the top
    Flower head shape
    • the flower head is cup-shaped (the sides diverge, then curve upwards and become parallel)
    • the sides of the flower head are roughly parallel, like a cylinder
    Flower type in flower heads
    the flower head has disk flowers only, and lacks the strap-shaped flowers
    Height of flower head base
    8–40 mm
    Inflorescence branching (Solidago)
    NA
    Inflorescence shape
    the flower heads grow in clusters from the axils of the branches or leaves
    Ovary beak
    there is a beak on the ovary
    Ovary hair type
    the ovary has no hairs on it
    Ovary hairs
    the ovary has no hairs on it
    Ovary profile
    in profile, the ovary is roughly elliptical (widest in the middle, tapering to both ends)
    Ray flower color
    NA
    Ray flower reproductive parts
    NA
    Ray flowers
    0
    Ray length
    0 mm
    Reproductive system
    the flowers on the plant may have either carpels or stamens, but always in separate flowers
    Style branch number
    • the style has one branch
    • the style has two branches
    Width of flower head base
    At least 2 mm

  • Fruits or seeds

    Dispersal unit
    the entire flower head falls off or disperses as a unit
    Number of pappus parts
    0
    Ovary length in developed fruit
    15–30 mm
    Seed hair tuft bases
    NA
    Seed hair tuft color
    NA
    Seed hair tuft details
    NA
    Seed hair tuft length
    0 mm
    Seed hair tuft tips
    NA
    Seed hairs uniform
    NA
    Seed tuft scale number
    0
    Seed tuft type
    there is no pappus on the ovary
    Top of disk flower ovary
    NA
    Tuft or plume on fruit
    there is no plume, or the plume is made up of scales, awns, a crown, or a rim

  • Glands or sap

    Leaf blade glands
    the leaf blades have no glandular (translucent) dots or scales
    Sap
    the sap is clear and watery

  • Growth form

    Growth form
    the plant has one or more free-standing stems
    Plant lifespan
    the plant is annual, it lacks evidence of previous years' growth
    Spines on plant
    the plant has no spines
    Underground organs
    there is a thickened taproot on the plant

  • Leaves

    Hairs on underside of leaf blade
    the underside of the leaf is fuzzy or hairy
    Hairs on upper side of leaf blade
    the upper side of the leaf is fuzzy or hairy
    Leaf arrangement
    alternate: there is one leaf per node along the stem
    Leaf blade base
    the leaf has a distinct petiole
    Leaf blade base shape
    • the base of the leaf blade is truncate (ends abruptly in a more or less straight line as though cut off)
    • the base of the leaf is cordate (heart-shaped) or sagittate (arrow-shaped)
    Leaf blade bloom
    the underside of the leaf has no noticeable bloom
    Leaf blade edges
    • the edge of the leaf blade has lobes, or it has both teeth and lobes
    • the edge of the leaf blade has teeth
    Leaf blade hairs
    the leaf blade has simple hairs with no glands, and not tangled or wooly
    Leaf blade length
    40–180 mm
    Leaf blade shape
    • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    • the leaf blade is triangular, with the stalk or attachment point on one of the sides
    Leaf blade surface colors
    • there are noticeable spots, patches or stripes on the upper surface of the leaf
    • there is no noticeable color variation on the upper surface of the leaf
    Leaf blade tip
    the tip of the leaf blade is acute (sharply pointed)
    Leaf blade veins
    the leaf blade has one main vein running from the base towards the tip
    Leaf blade width
    30–180 mm
    Leaf disposition
    the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
    Leaf spines
    there are no spines on the leaf edges
    Leaf stalk
    the leaves have leaf stalks
    Leaf stalk length
    20–140 mm
    Leaf tip extension
    NA
    Leaf type
    leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Leaflet number
    0
    Specific leaf type
    • the leaf has lobes that radiate from the base, somewhat like a hand
    • the leaves are simple (i.e., lobed or unlobed but not separated into leaflets

  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • brackish or salt marshes and flats
    • dunes
    • edges of wetlands
    • man-made or disturbed habitats
    • marshes
    • sea beaches
    • shores of rivers or lakes

  • Scent

    Plant odor
    the plant does not have much of an odor

  • Stem, shoot, branch

    Flowering stem cross-section
    the flowering stem is circular, or with lots of small angles
    Leaves on stem
    there is at least one full leaf above the base of the flowering stem
    Stem bloom
    there is no powdery or waxy film on the stem
    Stem internode hairs
    • the stem has hairs between the nodes
    • the stem has no hairs between the nodes
    Stem wings
    • the stem does not have wings on it
    • the stem has wings on it that run down the stem from the leaf nodes

Wetland status

Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)

In New England

Distribution

Connecticut
present
Maine
present
Massachusetts
present
New Hampshire
present
Rhode Island
present
Vermont
present

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

var. canadense

Massachusetts
widespread (S-rank: S5)

var. glabratum

Massachusetts
fairly widespread (S-rank: S4)

var. strumarium

Massachusetts
not applicable (S-rank: SNA)

Subspecies and varieties

Xanthium strumarium var. canadense is native (at least in part) and known from CT, MA, ME, NH, RI, VT. It is the more common form.X. strumarium var. glabratum (DC.) Cronq. is native (at least in part) and known from CT, MA, VT.X. strumarium L. var. strumarium is non-native and known from MA, VT.

From Flora Novae Angliae dichotomous key

2.  Xanthium strumarium L. n

rough cocklebur.  2a. Xanthium canadense P. Mill.; X. echinatum Murr.; X. glanduliferum Greene; X. italicum Moretti; X. oviforme Wallr.; X. pensylvanicum Wallr.; X. speciosum Kearney; X. strumarium L. var. pensylvanicum (Wallr.) M.E. Peck;  2b. Xanthium americanum Walt.; 
 X. chasei Fern.; X. chinense P. Mill.; X. curvescens Millsp. & Sherff; X. cylindraceum Millsp. & Sherff; X. echinellum Greene; X. globosum Shull; X. inflexum Mackenzie & Bush; X. orientale L. • CT, MA, ME, NH, RI, VT. River banks, river shores, especially those of sand and gravel substrate, lake shores, waste areas, coastal beaches, borders of saline marshes, dune hollows.

1a.  Fruiting carpellate involucres (17–) 20–40 mm long and 12–30 mm thick, terminated by 2 beaks 3–11 mm long; prickle bases of carpellate involucres spreading-pubescent and sometimes also stipitate-glandular [Fig. 477] … 2a. X. strumarium var. canadense (P. Mill.) Torr. & Gray

1b.  Fruiting carpellate involucres 8–20 (–25) mm long and 4–18 mm thick, terminated by 2 beaks 1–7 mm long; prickle bases of carpellate involucres glabrous or puberulent and sometimes also glandular-puberulent and/or with sessile glands

2a.  Carpellate involucres terminated by 2 incurved or, less commonly, straight beaks, the fruiting ones usually pale or light brown; petioles usually scabrous; leaf blades usually scabrous adaxially … 2b. X. strumarium var. glabratum (DC.) Cronq.

2b.  Carpellate involucres terminated by 2 straight beaks, the fruiting ones green to yellow-green; petioles minutely and softly pilose; leaf blades weakly scabridulous adaxially 
 … 2c. X. strumarium var. strumarium

Variety canadense is native (at least in part) and known from CT, MA, ME, NH, RI, VT. It is the most frequently encountered variety in New England. Variety glabratum is native (at least in part) and known from CT, MA, VT; also reported from RI by George (1992), but specimens are unknown. Variety strumarium is non-native and known from MA, VT.

Native to North America?

Yes and no (some introduced)

Sometimes confused with

Xanthium spinosum:
leaf blades lanceolate, tapering to the base, abaxially gray to white and densely strigose, and plants with 3-forked, axillary spines (vs. X. strumarium, with leaf blades ovate to reniform, truncate to cordate at the base, abaxially +/- green, hirtellous, and plants without axillary spines).

Synonyms

  • Xanthium canadense P. Mill.
  • Xanthium echinatum Murr.
  • Xanthium glanduliferum Greene
  • Xanthium italicum Moretti
  • Xanthium oviforme Wallr.
  • Xanthium pensylvanicum Wallr.
  • Xanthium speciosum Kearney
  • Xanthium strumarium var. pensylvanicum (Wallr.) M.E. Peck

Family

Asteraceae

Genus

Xanthium