Yellow star-thistle
General poisoning notes:
Yellow star-thistle (Centaurea solstitialis) has the same toxic effect on horses as Russian thistle, which is more toxic. Chewing disease becomes incurable once clinical signs are present (Cordy 1987). See the general notes under Russian thistle.
Description:
Centaurea solstitialis is a grayish-green plant with multiple rigid stems that extend in all directions from the base, forming a bushy-looking cluster that can reach 2 metres (6.6 ft) in height and more than that in diameter. It produces bright yellow flowers ringed with long, sharp spines. The plant grows quickly and is very competitive. It bears a taproot that can reach 1 metre (3.3 ft) deep into the soil, allowing it to thrive during dry, hot summers. It is versatile in its growth patterns, and can adapt to drought or low soil moisture content by producing smaller plants with fewer seeds during dry years.
Centaurea solstitialis L.
Nomenclature:
Scientific Name: Centaurea solstitialis L.
Vernacular name(s): yellow star-thistle, golden starthistle, yellow cockspur and St. Barnaby's thistle (or Barnaby thistle)
Scientific family name: Compositae
Vernacular family name: composite
Geographic Information:
Manitoba, Saskatchewan, Ontario.
Toxic parts:
All parts, leaves, stems.
Toxic plant chemicals:
Unknown chemical.
Animals/Human Poisoning:
Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.
Horses
General symptoms of poisoning:
Death, incoordination, water intake, reduced.
