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Centaurea solstitialis
Also called St. Barnaby's Thistle, Barnaby Star Thistle, Barneby Star Thistle, St Barnaby's Thistle, Geeldissel, Golden Star Thistle, Yellow Centaury
Yellow star-thistle is a thorny annual weed from the daisy family, native to the Mediterranean region and invasive in many other areas. It grows best in dry, disturbed, sunny ground and dies after setting seed each summer.
Centaurea solstitialis, the yellow star-thistle, is a species of thorny plant in the genus Centaurea, which is part of the family Asteraceae. A winter annual, it is native to the Mediterranean Basin region and invasive in many other places. It is also known as golden starthistle, yellow cockspur and St. Barnaby's thistle (or Barnaby thistle).
Grazing of the plant by horses can cause nigropallidal encephalomalacia or "chewing disease", a neurological condition. The disease generally follows consumption of 60–200% of the horse's body weight over an extended period of a month or more, or 2.3–2.6 kilograms (5.1–5.7 pounds) of star-thistle per 100 kg (220 lb) body weight per day. Though star-thistle is most dangerous when it is the only plant available or is delivered as a contaminant in dried hay, horses may develop a taste for it and seek it out. Many other grazing species, including mules and burros, are not affected.
Centaurea solstitialis is considered a weed also on its native European range (e.g., Turkey, Greece, Italy, France, Spain). Consequently, it inhabits highly disturbed ruderal habitats, being typically found on roadsides and cereal crop margins. After introduction in several parts of the world as an exotic species (e.g., Australia, Argentina, Chile, the United States), it has developed local adaptations to the different habitats colonized, and an incipient level of reproductive isolation between native and non-native ranges has been detected—a case of ecological speciation.
Although the spines make the plant a pain to deal with, it produces a light honey.
Centaurea behen · Dusty miller · Cornflower · Fiordaliso di Capraia · Maltese star-thistle · Perennial Cornflower · Common Knapweed · Spotted knapweed · Centaurea tchihatcheffii
Text excerpted from the Wikipedia article Centaurea solstitialis by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
Pet safety from the ASPCA toxic and non-toxic plant lists.
