Capture of a common “musk thistle” (Carduus nutans) in bloom by the banks of the Grand River near Waterloo,Ontario, Canada.
“Musk thistles” are thistles of the genus Carduus nutans, flowering plants of the daisy family (Asteraceae) and are known for their beautiful magenta to purple radial blooms and their thorny sharp edged leaves. The flower heads commonly droop to a 90° to 120° angle from the stem when mature, hence its alternate name of “Nodding thistle”. Each plant may produce thousands of straw-colored seeds adorned with plume-like bristles. They are 4 to 6cm across, with purple-red bracts.
They are indigenous to regions of Europe and Asia except in the far north.
It was introduced into the eastern North America in the early 1800s and has a long history there as an invasive species. It has been declared a noxious weed in Australia, many U.S. states and Canadian provinces. Some farmers spend many hours attempting to rid them from farm ground, mostly pastures. It is equally noxious to farming operations in New Zealand.