SLEEPY CATCHFLY, Silene antirrhina L. 1, plant; 2, flower with pod; 3, upper portion of stem; 4, flower enclosed by calyx; 5, seed. Annual, reproduced by seeds only. Stem slender, erect, 1 to 2-1/2 feet (30 to 75 cm) high, sparingly branched, upper part often of darker color and sticky. Leaves opposite, not petioled, linear, although those at base are somewhat broader. Flowers small, 1/8 inch (3 mm) across, pink with 5 petals, enclosed at base by ovoid calyx. Seeds kidney-shaped, very small, lead-colored, covered with knobs. Found especially on dry, light soil. Important weed in clover seed fields, because seeds are difficult to remove from the clover seed.