Yellow Starthistle (Centaurea solstitialis L.)

YELLOW STARTHISTLE

(Centaurae solstitialis L.)

GROWTH HABIT:  Annual, erect, rigid branching stems.

LEAVES:  Basal leaves deeply lobed, upper leaves not lobed, small, sharply pointed.

STEMS:  Rigid, covered with a cottony fiber, to 30 inches tall, winged structures.

FLOWERS:  Yellow, terminal, flower bracts are tipped with straw-colored, ¨ú inch torn.

ROOTS:  Taproot.

SEEDS:  Smooth, light-colored, often darker mottled, ¨û inch long, notched just above the base.

OTHER:  Causes ¡°chewing disease¡± in horses.