Scientific Name: Centaurea jacea (Asteraceae). There is a plethora of synonyms, varieties and subspecies, and considerable taxonomic confusion and argument about this species. Includes C. nigra and C. jacea subsp nigra.
English Name: Common Knapweed, Lesser Knapweed, Brown-rayed Knapweed, Black Knapweed, Slender Knapweed, Hardhead.
French Name: la Centaurée noire.
5 Key Characters:
Lookalikes: Greater Knapweed C. scabiosa, which has deeply divided leaves and different involucural bracts.
Habitat: Grasslands, roadsides, waste ground, meadows, thickets and shady places.
Flowering Period: June-July-August-September.
Status: Very common. The most widespread here is C. jacea subsp nigra, which rarely has a 'crown' of long marginal florets.
Photographed by Loire Valley Nature:
English Name: Common Knapweed, Lesser Knapweed, Brown-rayed Knapweed, Black Knapweed, Slender Knapweed, Hardhead.
French Name: la Centaurée noire.
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| C. jacea (probably not subsp nigra) |
5 Key Characters:
- very variable!
- leaves usually lanceolate.
- pinky-purple flowers may or may not have long marginal florets, depending on variety or subspecies.
- plant roughly hairy and tough stemmed.
- the various varieties and subspecies mainly identified by examination of the involucural (flower head) bracts -- a dark art to which very few botanists will commit themselves.
Lookalikes: Greater Knapweed C. scabiosa, which has deeply divided leaves and different involucural bracts.
Habitat: Grasslands, roadsides, waste ground, meadows, thickets and shady places.
Flowering Period: June-July-August-September.
Status: Very common. The most widespread here is C. jacea subsp nigra, which rarely has a 'crown' of long marginal florets.
Photographed by Loire Valley Nature:
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