The Thistle tribe contains many brightly colored spiny species.

Centaurea

biebersteinii

Spotted Knapweed

Knapweeds are considered invasive species throughout much of the southwest.
Cirsium

undulatum

Wavyleaf Thistle

Thistles comprise the genera of Cirsium and Carduus.
Arctium

minus

Common Burdock

Burdocks are large plants with burry fruits.
Carduus

nutans

Musk Thistle