Centaurea jacea
| Centaurea jacea | |
|---|---|
| Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Asterales |
| Family: | Asteraceae |
| Genus: | Centaurea |
| Species: | C. jacea
|
| Binomial name | |
| Centaurea jacea | |
| Synonyms | |
| |
Centaurea jacea, brown knapweed[1] or brownray knapweed, is a species of herbaceous perennial plants in the genus Centaurea native to dry meadows and open woodland throughout Europe.
In Britain and America, it is often found as a hybrid[2] of black knapweed, Centaurea nigra.[3] Unlike the black knapweed, the flower heads always look as if they are rayed, forming a more open star rather than a brush-like tuft.
Distribution
Brown knapweed is native to Europe, extending to West Siberia and Caucasus. It has been introduced in North America, where it is often considered an invasive species, particularly in the northeastern United States and Canada. [4]
Description
Habit
Plant up to 20-100 cm tall.
Stem
Single or branched, straight erect, angular and rough.
Leaves
Stem leaves gathered in a rosette, single, ovate to lanceolate, often pinnately-arched, petioled. Stem leaves sedentary, entire-edged with a tapered base.
Flowers
Collected in baskets set singly at the top of the stems, 2-6 cm wide. The basket has a perianth 1-2 cm long, egg-shaped. The leaves of the sheath are rounded, entire-edged, or crested, pale to brown in color. Flowers are tubular, purple-purple, occasionally white. Marginal flowers larger, fertile with a distinctly bipinnate corolla, inner flowers hermaphrodite. The stamens push the anthers upward under the touch of an insect, making it easier for them to carry pollen. Flowering occurs from June to October.
Fruits
Shiny achenes, inverted ovate, about 3 mm long. [5][6]
References
- ^ BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
- ^ "Centaurea x_moncktonii in Flora of North America @ efloras.org". www.efloras.org. Retrieved 24 October 2022.
- ^ Rose, Francis (1981). The Wild Flower Key. Frederick Warne & Co. pp. 386–387. ISBN 0-7232-2419-6.
- ^ "Centaurea jacea L. | Plants of the World Online | Kew Science". Plants of the World Online. Retrieved 2025-07-07.
- ^ "MAIT - Mid-Atlantic Invaders Tool".
- ^ "Centaurea jacea (brown knapweed): Go Botany". gobotany.nativeplanttrust.org. Retrieved 2025-07-07.
External links
- Media related to Centaurea jacea at Wikimedia Commons