Cirsium

Cirsium is a genus of flowering plants in the family Asteraceae. It is one of many genera with the common name being thistles. Other genera known as thistles include "Carduus", "Cynara", "Onopordon", and "Silybum".
They are mostly native to Eurasia and northern Africa. There are about 60 species in North America (although many species have been naturalized outside their native ranges).
Most species are considered weeds. "Cirsium vulgare" is listed as a weed in nine US states. Some species are planted in gardens for their beauty and to attract butterflies.