Lathraea L., commonly called toothwort, is an Eurasian genus of about 5 perennial species in the family of Orobanchaceae. The Latin name derives from the greek word for "stealthy", which is quite fitting for a plant completely underground when not in flower. All members are holoparasites, lacking any chlorophyll and connecting their rhizomes to the root system of various trees to get the nutrients they need.
Lathraea squamaria L. is a widespread European species, mostly living on Alder, Populus, Beech or Hazel. It is slow growing and needs about 10 years until it starts flowering, but will eventually reach up to 2 meters rhizome length and up to 5kg weight, all underground. Pictures by Martin Bohnet from plants in habitat on the Swabian Jura.