any of various western American plants of the genus Grindelia having resinous leaves and stems formerly used medicinally; often poisonous to livestock

Rosinweed (Silphium) is a genus of about 20 species of flowering plants in the family Asteraceae, native to eastern North America. They are herbaceous perennial plants growing to 0.5-4 m tall, with yellow (rarely white) flowerheads.