YELLOW STAR-THISTLE

Centaurea solstitialis

Daisy & Dandelion Family [Asteraceae]

month8jul month8july month8aug month8sep month8sept

status
statusZneophyte
flower
flower8yellow
morph
morph8actino
petals
petalsZMany
type
typeZclustered
stem
stem8round
stem
stem8ribbed
toxicity
toxicityZlowish
contact
contactZhigh
sex
sexZbisexual

11th Oct 2020, Brook, Coastguard Cottages. Photo: (CC by 2.0) Geoff Toone
A spreading or erect plant with yellow flowers similar to Sow-thistles and growing up to 60cm high.


11th Oct 2020, Brook, Coastguard Cottages. Photo: (CC by 2.0) Geoff Toone
The petals are thin, linear numerous and uniformly deep-yellow like those of Safflower but spreading out more and less orange.


11th Oct 2020, Brook, Coastguard Cottages. Photo: (CC by 2.0) Geoff Toone
The leaves are variously pinnately-lobed to dentate
The spines are vicious, long and very sharp!


11th Oct 2020, Brook, Coastguard Cottages. Photo: (CC by 2.0) Geoff Toone
The capitula is more or less discoidal and covered with cottony white hairs almost flat on the surface.


11th Oct 2020, Brook, Coastguard Cottages. Photo: (CC by 2.0) Geoff Toone


11th Oct 2020, Brook, Coastguard Cottages. Photo: (CC by 2.0) Geoff Toone
The spines are shorter near the base of the phyllaries, the longest being the summit spike, which is longer than 1cm.


11th Oct 2020, Brook, Coastguard Cottages. Photo: (CC by 2.0) Geoff Toone
On older specimens the linear petals remain on the plant as they turn fawn coloured. These will be the seeds for next year.


11th Oct 2020, Brook, Coastguard Cottages. Photo: (CC by 2.0) Geoff Toone
An upside-down seed-head.


11th Oct 2020, Brook, Coastguard Cottages. Photo: (CC by 2.0) Geoff Toone
A seed head beginning to crack open.


11th Oct 2020, Brook, Coastguard Cottages. Photo: (CC by 2.0) Geoff Toone
The seed pod cracked open complete with the white hairs to help the seeds disperse when carried away by the wind.


It is casual neophyte which was formerly naturalised in arable fields - usually those containing Lucerne - but is now seemingly only occasionally found on waste ground mostly carried by wool or from bird-seed. It once occurred throughout Britain but is now to be found scattered in Southern Britain.

Easily mistaken for : Yellow Thistle (Cirsium eristhales) but only if you can find any! It was naturalised in a quarry in North Somerset in the 1980's but doesn't appear to have been reported again. It belongs to a differing genus: Cirsium rather than Centaurea.


  Centaurea solstitialis  ⇐ Global Aspect ⇒ Asteraceae  

Distribution
 family8Daisy & Dandelion family8Asteraceae
 BSBI maps
genus8Centaurea
Centaurea
(Knapweeds)

YELLOW STAR-THISTLE

Centaurea solstitialis

Daisy & Dandelion Family [Asteraceae]