Lathraea squamaria, the common toothwort, is a species of toothwort. It is parasitic on the roots of hazel and alder, occasionally on beech, in shady places such as hedge sides. It consists of a branched whitish underground stem closely covered with thick, fleshy, colourless leaves, which are bent over so as to hide under the surface; irregular cavities communicating with the exterior are formed in the thickness of the leaf.