释义 |
Definition of knapweed in English: knapweednoun ˈnapwiːdˈnæpwid mass nounA tough-stemmed Eurasian plant that typically has purple thistle-like flower heads, occurring chiefly in grassland and on roadsides. Genus Centaurea, family Compositae: several species, including the widespread common (or lesser) knapweed (C. nigra) (also called hardheads) Example sentencesExamples - The oil from the seeds of cotton thistles was extracted for fuel and knapweed, centaurea scabiosa, was believed to promote healing of bruises and wounds.
- Currently, most producers apply chemicals on rangeland in spring or summer, when knapweed begins to flower, but research is showing that fall application may be preferable.
- Invasive weeds such as cheatgrass and knapweeds have settled on some 125 million acres of the American West.
- Spotted knapweed is not killed by fire, but sagebrush is.
- In Montana, gall flies released to limit knapweed turn out to provide a food bonanza for white-footed mice.
Origin Late Middle English (originally as knopweed): from knop (because of its hard rounded involucre or ‘head’) + weed. Definition of knapweed in US English: knapweednounˈnæpwidˈnapwēd A tough-stemmed Eurasian plant that typically has purple thistle-like flower heads, occurring chiefly in grassland and on roadsides. Genus Centaurea, family Compositae: several species, including the widespread black knapweed (C. nigra) (also called hardheads) Example sentencesExamples - Invasive weeds such as cheatgrass and knapweeds have settled on some 125 million acres of the American West.
- The oil from the seeds of cotton thistles was extracted for fuel and knapweed, centaurea scabiosa, was believed to promote healing of bruises and wounds.
- Currently, most producers apply chemicals on rangeland in spring or summer, when knapweed begins to flower, but research is showing that fall application may be preferable.
- In Montana, gall flies released to limit knapweed turn out to provide a food bonanza for white-footed mice.
- Spotted knapweed is not killed by fire, but sagebrush is.
Origin Late Middle English (originally as knopweed): from knop (because of its hard rounded involucre or ‘head’) + weed. |