Fleabane
WordNet
noun
(1) Common North American weed with linear leaves and small discoid heads of yellowish flowers; widely naturalized throughout temperate regions; sometimes placed in genus Erigeron
(2) Any of several North American plants of the genus Erigeron having daisylike flowers; formerly believed to repel fleas
(3) Hairy perennial Eurasian herb with yellow daisylike flowers reputed to destroy or drive away fleas