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Content tagged with "thistle"

Photo of a bull thistle flowerhead.

Bull Thistle

Cirsium vulgare
Bull thistle is a weedy introduction from Europe, found statewide. To tell it from our other thistles, note its stems with spiny-margined wings, and its leaves with the upper surface strongly roughened with stiff, spiny bristles.

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Photo of bull thistle, a spiny thistle with a pink flowerhead

Bull Thistle

Bull thistle is a weedy introduction from Europe, found statewide. To tell it from our other thistles, note its stems with spiny-margined wings, and its leaves with the upper surface strongly roughened with stiff, spiny bristles.

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Photo of a bull thistle flowerhead.

Bull Thistle (Flowerhead)

The flowerheads of bull thistle are reddish purple to purple, with a prominent involucre (the flowerhead base, covered by leaflike bracts), which is covered with a fine, cobweb-like silk. Spiny bracts grow right up to the flowerheads.

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Photo of bull thistle showing stems with spiny wings.

Bull Thistle (Stem)

Bull thistle has stems with spiny-margined wings. This trait, combined with the pink flowerheads, is a quick way to identify this common, weedy species.

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Photo of Canada thistle flowers

Canada Thistle

Canada thistle is a native to Eurasia and arrived on our continent probably before the Revolutionary War—most likely mixed in agricultural seed. A bad weed of crop fields and rangeland farther north, it causes problems in Missouri, too.

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Photo of Canada thistle flowers

Canada Thistle

Cirsium arvense
Canada thistle is a native to Eurasia and arrived on our continent probably before the Revolutionary War—most likely mixed in agricultural seed. A bad weed of crop fields and rangeland farther north, it causes problems in Missouri, too.

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Photo of common teasel, blooming flowerhead, showing lavender flowers.

Common Teasel (Flowerhead)

Common teasel typically has lavender flowers, though occasionally a rare plant produces white flowers. It has been present in our state since before 1880 and is not as aggressive as cut-leaved teasel.

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Photo of common teasel flowering heads.

Common Teasel (Flowerheads)

“Infestation” is the term for what teasels are doing in Missouri. Learn to identify these thistlelike plants, and help to control the weedy spread of these tough, prickly invaders.

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Photo of common teasel showing opposite, unlobed leaves.

Common Teasel (Leaves)

The stem leaves of common teasel are not lobed, and though they are often fused at the base, they don’t form a cuplike structure around the stem.

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Photo of a cornflower, closeup of a flowerhead.

Cornflower (Bachelor’s Button) (Flowerhead)

A member of the thistle tribe of composites, cornflower lacks true ray florets; instead, the outer florets of each head have enlarged, flaring corolla tubes that at a glance look something like the strap-shaped extensions of true ray florets.

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