Field Madder is an annual, mat forming herb with rings of 4-6 narrow pointed leaves with tiny forward pointing spines on the upper surface and edges. It has clusters of 4-8, small, 4 petalled, purple to pink or white flowers from September to December surrounded by 8 floral leaves at the ends of the branches. The stems are hollow and square with downward pointing, tiny spines on the corners, The mature plant is erect in habit when small but as it grows becomes semi-erect and spreading or mat forming, with the ends of the branches erect.