Cynareae is derived from the Greek kuon, meaning dog. The phyllaries in the Cynareae are said to resemble dogs teeth. Cirisium and Carduus, genera containing thistles and Centaurea, the invasive knapweeds, are members of the Cynareae. Thistle tribe members are typically spiny or prickly, have only disk flowers, and possess leaves with divided edges.

Centaurea

biebersteinii

Spotted Knapweed
Knapweeds are an invasive Eurasian species. They are considered an invasive or noxious weed and attempts are made to destroy them in many areas. The flowers are pretty. This specimen was growing on gravel slopes on the Waldo Canyon Trail just east of Colorado Springs, Colorado.
Cirsium

undulatum

Wavyleaf Thistle
Thistles are prickly plants with flower heads composed of disk flowers. They differ in flower color and leaf shape. This wavyleaf thistle was growing on the Barr Trail to Pikes Peak at about 7,000 foot elevation.
Arctium

minus

Common Burdock
Burdocks have bright disk flowers and burry fruits. This specimen was growing at the Lookout Mountain Visitor Center above Golden, Colorado. Burdocks have large leaves, the specimen here was 8 inches long and six inches wide. Height of the plant was nearly a meter.
Carduus

nutans

Musk Thistle
Thistles occur in two genera, Carduus and Cirsium. Carduus nutans specimens have been observed on the mesas East of Taos, New Mexico, on the Waldo Canyon Trail East of Colorado Springs, and on the gravel shoreline of Grand Lake, Colorado.