SPANISHNEEDLES, Bidens bipinnata L. 1, lower portion of plant; 2, upper portion of stem and flower heads; 3, mature flower; 4, seed. Annual, taprooted with numerous side branches. Stems erect, smooth, branching in upper portions. Leaves with petioles, divided several times into fine segments; borne opposite at nodes of both stems and branches. Flower heads found singly at the ends of long, slender, nearly leafless branches, pale yellow ray flowers surrounding yellow disk flowers. Seeds about 1/2 inch (1.3 cm) long, narrow, sharp-pointed, brown to black, bearing 3 to 4 stiff spines covered with short, down-pointed bristles. Found in waste places and grain stubble fields.