Though we call it Canada Thistle, it is actually from Europe and Asia. It is unwanted nearly everywhere. It is a nuisance because its lateral roots send up new shoots. Most thistles take two years to flower. In the first it develops a rosetta only. (An picture of a rosetta can be seen in the Bull Thistle displayed later in this section.)
It is a small blossom as can be seen in comparison to the wasp.
This is a Canada Thistle in several stages of development. Male and female flowers are on separate plants.
Here they can be seen spreading just a year after being sprayed by Logan County.
Another stand of the plant, this time going to seed.