WordNet sense 1 (prickly bushy Eurasian plant; a troublesome weed in central and western United States):

Russian thistle, Russian cactus, Russian tumbleweed, Salsola kali tenuifolia

WordNet sense 2 (bushy annual weed of central North America having greenish flowers and winged seeds):

winged pigweed, Cycloloma atriplicifolium

WordNet sense 3 (bushy plant of western United States):

Amaranthus albus, Amaranthus graecizans