"tarweeds" in the noun sense
1. tarweed
any of various resinous glandular plants of the genus Madia of western North and South America
2. gumweed, gum plant, tarweed, rosinweed
any of various western American plants of the genus Grindelia having resinous leaves and stems formerly used medicinally often poisonous to livestock
Source: WordNet® (An amazing lexical database of English)
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