Russian thistle

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Russian thistle mature leaves and bracts

Russian thistle branches

Russian thistle

Russian thistle

Russian thistle inflorescences

Russian thistle

Russian thistle inflorescences

Morphology

Stem

Erect, much-branched from or near base, ridged, often red- or purple-striped, sparsely coarse-hairy to glabrous; branches many, arching upward, forming rounded bush.

Leaves

Alternate, simple, sessile to clasping, thread-like to narrowly linear, .5 to 3.2 inches long, to 1/25 inch wide, reduced upwards, succulent, glabrous to pubescent; tip spiny; base broad; margins entire to minutely toothed; initial leaves long, thread-like, soft; mature leaves short, scale-like, tipped with stiff spines.

Inflorescence

Spike-like, 1 to 4+ inches long, terminal on branches, densely flowered toward tip, interrupted near base; flowers solitary in upper axils of leaf-like bracts; bracts spreading, often curved back, ovate to triangular, 1/8 to 1/3 inch long, glabrous or pubescent at base, tips strongly spiny.

Flower

Perfect, sessile, inconspicuous, perianth pentagon-shaped, greenish; perianth segments 5, fused, thickened, glabrous, with prominent membranous wings at maturity; wings to 1/10 inch wide; tips blunt to weakly pointed; margins entire to scalloped; stamens 3-5, initially included, later protruding; stigmas 2-3, thread-like.

Fruit

Fruit enveloped by persistent perianth segments; bladder-like, nearly circular, flattened, 1-seeded, 1/6 to 2/5 inch in diameter; seeds tiny, round, 1/16 to 1/12 inch in diameter, black, smooth, shiny. Fruit becomes reddish when ripe.

Ecology

Habitat

Open, disturbed sites, roadsides, overgrazed rangeland, cultivated fields, along railroads, waste areas; often in sandy soils.

Distribution

Throughout Kansas

Reproduction

By seed. Russian thistle is a prolific seed producer. The stems break at ground level and roll in the wind causing the seeds to fall. Thus the common name tumbleweed. The seeds require only limited moisture to germinate.

Practical Information

Toxicity

Accumulates nitrates. Toxic to livestock. If consumed in excess, it can lead to diarrhea, weakness, labored breathing, and even death.

Forage Value

Fair when young for sheep and cattle but no value when mature.

Uses

Native Americans in the Southwest applied chewed plants to insect stings, steeped ashes from the plant and used the liquid internally and externally to treat influenza and smallpox. The sprouts were boiled and eaten with butter or mutton fat, young fresh sprouts were used in salads, and the seeds were roasted for food. Provides cover for pheasants. Songbirds and small mammals eat the seeds and foliage.

Additional Notes

Synonyms

Alternative scientific names that have been used for this plant.