| 释义 |
py·re·thrum
\pīˈrēthrəm also -reth-\ noun
Etymology: New Latin, from Latin, pellitory, from Greek pyrethron, from pyr fire; from the spicy taste of the root
1.
a. capitalized, in some especially former classifications : a genus of composite plants with finely divided leaves that are now usually included in the genus Chrysanthemum
b. -s : any of various chrysanthemums with finely divided and often aromatic leaves: as
(1) : a chrysanthemum (as C. coccineum or C. cinerariaefolium) that is a source of insecticides
(2) : any of several garden perennials that are derived from the Asiatic species (C. coccineum) and have white, pink, red, or rarely lilac flowers in late spring — called also painted daisy
2. -s
a. or pyrethrum flowers : an insecticide consisting of the dried powdered flowers of a Dalmatian pyrethrum (Chrysanthemum cinerariaefolium) or either of two Asiatic pyrethrums (C. coccineum and C. marschallii) — called also respectively Dalmatian insect powder, Persian insect powder
b. or pyrethrum extract : an extract of the powdered flowers containing pyrethrins and cinerins and used in insecticidal sprays |