Lathraea clandestina is a holoparasite that has neither leaves nor chlorophyll and draws its food from the roots of its hosts via suckers known as haustoria. The subterranean part, which can weigh several kilograms, consists of white stems covered with fleshy scales. The flowers are 40 to 50 mm, with long pedicels; they appear near to the ground in April - May. The normal colour of the flowers is purple or purplish-violet, but rarely colonies with paler, pink or even wholly white flowers may be encountered. Mature fruits can project their 4 to 5 large seeds some distance into the surrounding area. The plant then disappears from the surface until the following spring. Seedlings grown from seed will take about ten years to produce their first flowers. The total absence of green indicates the parasitic nature of the species which, free of chlorophyll, attaches to the roots of the host to harvest the nutrients necessary for its growth. Given that it flowers and produces fruits during the rise of the sap in the spring, the hosts appear to suffer very little from this parasitism.