1911 Encyclopædia Britannica/Toothwort

TOOTHWORT, the popular name for a small British plant of curious form and growth, known botanically as Lathraea squamaria. It grows parasitically on roots, chiefly of hazel, in shady places such as hedge sides. It consists of a branched whitish underground stem closely covered with thick fleshy colorless leaves, which are bent over so as to hide the under surface; irregular cavities communicating with the exterior are formed in the thickness of the leaf. On the inner wall of these chambers are stalked hairs, which when stimulated by the touch of an insect send out delicate filaments by means of which the insect is killed and digested. The only portions that appear above ground are the short flower-bearing shoots, which bear a spike of two-lipped dull purple flowers. The scales which represent the leaves also secrete water, which escapes and softens the ground around the plant. Lathraea is closely allied to another British parasitic plant, broom rape (0robanche).