Bull Thistle

Family: 
Asteraceae (daisies)
Description: 

 Biennial thistle with the upper stems and branches winged with a wavy, prickly tissue. Flowerheads typical of thistles, reddish purple to purple, with a prominent involucre (the flowerhead base, covered by leaflike bracts), which is covered with a fine, cobweb-like silk. Spiny bracts grow right up to the flowerheads; the middle and lower spines are spreading and yellow or straw-colored. Blooms June-September. Leaves alternate, deeply lobed, hairy, spiny, the upper surface with stiff bristles.

Similar species: There are nine species of Cirsium in Missouri. Bull thistle and Platte thistle (C. canescens) are the only two with stems having spiny-margined wings. Platte thistle has cream-colored flowers (rarely pale pink). It has been collected only once in Missouri, along a railroad in Jackson County in 1951.

Size: 
Height: to 7 feet.
Habitat and conservation: 
Native of Europe. Occurs in upland prairies and openings of disturbed upland forests; also pastures, railroads, roadsides, and open, disturbed areas.
Distribution in Missouri: 
Widely scattered statewide.
Human connections: 
The early leaves can be cooked as a potherb. To prepare the young bloom shoots, wear gloves and snip off leaves and spines. Peel outer rind from stem, cut into 3-inch sections, boil, and eat like an artichoke (dip in butter and pull stems through teeth, discarding stringy part).
Ecosystem connections: 
Thistles are a favorite of goldfinches, which eat the seeds and use the silky pappus ("parachutes") to line their nests. Several types of bees, butterflies, and other insects visit the flowers. A variety of caterpillars and beetles chew the leaves, though most mammals are put off by the spines.