Tordylium species are annuals or biennials, covered in long hairs. Their stems may be hollow or almost solid. The basal leaves are more-or-less undivided, and have usually disappeared when the plant flowers. The stem leaves are once pinnate. The flowers have persistent sepals and white petals, with those on one side much longer than the other. The fruits are about as long as they are wide. Their side ridges have whitish wings.