A life of deception
In the mountain forests of Shaanxi, at altitudes between 400 and 3,200 meters, lives an orchid with no leaves, no roots, and no chlorophyll. Gastrodia elata, known in Chinese as Tianma (天麻), is a full-time parasite, a mycoheterotroph that outsources its energy needs entirely to fungi. It cannot perform photosynthesis and has shed the genes required for it. Its life begins as a dust-like seed, one of up to 40,000 in a single fruit capsule, which must land near a specific fungus, usually of the genus Mycena, to germinate.
The Mycena fungus provides the initial nutrients for the seed to develop into a small structure called a protocorm. But the deception does not end there. For the orchid to grow its prized tuber, it must switch hosts. It lures a second, more substantial fungus: Armillaria mellea, the honey fungus. Armillaria is itself a parasite, a pathogen that attacks and feeds on tree roots. Gastrodia elata then parasitizes the parasite, digesting the Armillaria hyphae that enter its tissues and stealing the carbon the fungus took from the forest trees. This entire life cycle, from seed to a mature, flowering plant, can take nearly three years.