MAYWEED, Anthemis cotula L. 1, portion of plant in flower; 2, seedling; 3, seed. Annual or winter annual with short, thick taproot, reproducing only by seed. Stems erect, slender, much branched, nearly smooth, 12 to 18 inches (30 to 45 cm) tall. Leaves finely divided, with a strong disagreeable odor. Flower heads resembling those of a daisy, 1/2 to 1 inch (1.3 to 2.5 cm) across, borne singly at ends of branches. Ray flowers white, surrounding a mass of numerous small yellow disk flowers. Seeds brown, oblong,10-ribbed, with a rough seed coat. Found most commonly in abandoned fields, barnyards, and waste places. Also known as dog fennel.