Common Toadflax (or Yellow Toadflax) is a showy summer-flowering plant of waysides and grassland. It spreads by suckers, although the stem is stiff and upright. The leaves are long and glabrous, similar to those of flax (Linum), from which the plant gets the first part of its Latin name (Linaria).
The flowers have a long spur, with the nectar stored at its based, so that only long-tongued bees can force open the mouth of the corolla to reach the nectar. Some bees steal the nectar without pollinating the flower by biting through the spur.