West Highland Flora

Knapweed


Centaurea nigra

 

Centaurea nigra

Photo Carl Farmer
23 Sep 2002 Glenbrittle, Skye

Very common in grassland and moorland, roadsides, forestry rides, etc.

Flowerhead diameter c 3 cm

ID: Unmistakable in flower, except when the flowers are rayed making it look like Greater Knapweed.  This however has green involucral bracts, whereas Knapweed has brown ones.  Bract colour can also be used to separate the species when in bud or fruit.  Both Greater Knapweed and the rayed form of Knapweed are very rare in the area.

Other features: Flowers occasionally white.  Stem is swollen below the flowerhead.

 

Centaurea nigra

Photo Carl Farmer
23 Aug 2003 Staffin, Skye

  Centaurea nigra

Photo Carl Farmer
1 Aug 2004 Portree, Skye
Flower c 2.9 cm across at widest

 

Centaurea nigra

Photo Carl Farmer
15 Oct 2003 Portree, Skye
c 2 cm across at top

  Centaurea nigra

Photo Carl Farmer
30 Dec 2003 Scorrybreac, Skye

Left: Flowerhead after seeds dispersed.
The colour in the centre gradually fades.

Above: Winter stems


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