Tumbleweed

tumbleweed, any of several plants, particularly abundant in prairie and steppe regions, that commonly break from their roots at maturity and, drying into a rounded tangle of light, stiff branches, roll before the wind, covering long distances and scattering seed as they go. The Russian thistle—Salsola pestifera, of the family Chenopodiaceae (goosefoot family) and not a thistle—is one of the most frequent of the tumbleweeds. Naturalized from Asia, it has become a troublesome pest on Western prairies, although in drought years it may serve as forage in the spring before the spines form. Some other common tumbleweeds, such as Amaranthus albus or A. graecizans, are members of the family Amaranthaceae (amaranth family), naturalized from tropical America and now common weed pests in Western agricultural fields. Others are the hedge mustards (species of Sisymbrium) and several other plants of the goosefoot family, e.g., the winged pigweeds (Cycloloma) and the bugseeds (Corispermum). Tumbleweeds of the family Chenopodiaceae and Amaranthaceae are classified in the division Magnoliophyta, class Magnoliopsida, order Caryophyllales.

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tumbleweed

Plant that breaks away from its roots and is driven about by the wind as a light rolling mass, scattering seeds as it goes. Examples include pigweed (Amaranth retroflexus, a widespread weed in the western U.S.) and other amaranths, tumbling mustard, Russian thistle, the steppe plant Colutea arborea, and the grass Spinifex of Indonesian shores and Australian steppes.

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tumbleweed [′təm·bəl‚wēd]

(botany)

Any of various plants that break loose from their roots in autumn and are driven by the wind in rolling masses over the ground.

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Tumbleweed 

any one of several herbaceous plants growing in the steppes and deserts that, during seed ripening and, occasionally, earlier, form a globose mass. The stems break rather easily at the base, and the entire mass, when blown by the wind, rolls across the land, distributing its seeds over large distances. Tumbleweeds vary in diameter from a few cm to 1 m. They include annuals (rose of Jericho), biennials (a species of Falcaria of the family Umbelliferae), and perennials (several onion species of the family Liliaceae and several species of the genus Limonium of the family Plumbaginaceae).