Swaziland's Alien Plants Database

Xanthium spinosum L. ASTERACEAE spiny cocklebur, burweed, prickly burweed, spiny clotbur, dagger cocklebur, dagger weed, thorny burweed Invasive, Problem species Origin: Tropical America Growth Form: Herb Plant Description: Plant: Much-branched annual up to 1.2 m high; stems smooth, green or yellowish, armed with three-pronged spines. Leaves: Blue-green, sparsely hairy above, densely white-woolly below, entire or three-lobed, ± lanceolate, up to 60 mm long x 20 mm wide. Flowers: Greenish, inconspicuous in axils of leaves, October–April. Fruit: Burs ± 10 mm long, green, with reddish, hooked spines, turning yellowish then brown. Key Features: shorter, more branched habit but much narrower, divided, dark green leaves with a white underside and smaller burrs c.f. X. strumarium Control: manully, post-emergence, industrial herbicides or physical removal Comments: More information: Weeds & Invasive Plants Home Page NRCS Plants Database Illustration USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. Illustrated flora of the northern states and Canada. Photo - plant Gary A. Monroe @ USDA-NRCS PLANTS Database Photo - fruit/spines/leaves The Weeds Society of Western Australia

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