fleabane

Definition
(noun) hairy perennial Eurasian herb with yellow daisylike flowers reputed to destroy or drive away fleas Definition
(noun) any of several North American plants of the genus Erigeron having daisylike flowers; formerly believed to repel fleas Definition
(noun) common North American weed with linear leaves and small discoid heads of yellowish flowers; widely naturalized throughout temperate regions; sometimes placed in genus Erigeron