pyrethrum

A Eurasian perennial plant (Tanacetum coccineum) in the composite family, cultivated for its colorful flower heads and formerly used as a source of an insecticide.

A closely related perennial plant (Tanacetum cinerariifolium), commercially cultivated as the source of an insecticide.

An insecticide made from the dried flower heads of any of these plants.

A plant of the genus Pyrethrum; feverfew.

[capitalized] A former genus of composite plants of the tribe Anthemideæ, now included as part of the section Pyrethra in the genus Chrysanthemum, from which it was distinguished by achenes nearly equally from five- to ten-ribbed and crowned with a pappus, characters now known to vary in the same species.

A powdered preparation of pyrethrum, used as an insectifuge. Also called pyrethrum-powder. See insect-powder and buhach.

In pharmacy, the Anacyclus Pyrethrum, or pellitory-of-Spain.

Any of several perennial African plants of the genus Chrysanthemum, especially Chrysanthemum cinerariaefolium

Any of several insecticides obtained from these plants; pyrethrin