Native to southern Europe and the Mediterranean area, and now widely found in the western United States.
An annual or sometimes biennial weed that reproduces from seeds. Flowering occurs in mid to late spring and foliage usually is drying out by mid summer.
Mature plants can be over 4 feet tall, with numerous stems arising from the base and branching somewhat at their upper lengths. The stems are conspicuous as they are winged throughout their length with spiny flanges.
Leaves arise sparsely off of the stems without stalks, and each leaf is divided into from 2 to 5 pairs of deeply cut lobes, each lobe having a terminal spine. The lower surface of the leaves is slightly wooly.
Flower heads may occur in small clusters or singly on short stalks arising from the ends of the long stems. Flowers are purple to pinkish and do not fully open, remaining somewhat closed by the circle of bracts.
Characteristicts Important to Control:
Seeds mature by early summer so control must be accomplished prior to this.