A life in the dark
In the deep shade of old-growth beech and oak forests, the ghost orchid (Epipogium aphyllum) lives almost entirely underground. This plant has no chlorophyll, the green pigment that allows most plants to create energy from sunlight. Its pale, yellowish-white stem, which can grow up to 30 cm tall, has only small scales instead of leaves. The name aphyllum translates from Latin to "without leaves." Because it lacks the ability to photosynthesize, the ghost orchid is a full-time parasite.
It is a mycoheterotroph, meaning it gets its nutrients not from the sun, but from fungi. Specifically, it forms a parasitic relationship with fungal species that live in symbiosis with trees. The orchid's coral-like branching rhizome taps into the underground network of fungi—primarily from the Inocybe genus—and steals the carbon and nutrients that the fungi have acquired from their host trees. This allows the orchid to thrive in the dark forest understory, completely independent of sunlight. For years, or even decades, the rhizome can lie dormant, slowly gathering energy for a rare, unpredictable event.
The fleeting flower
The ghost orchid's appearance above ground is an infrequent event, usually occurring in the summer months between June and August. The plant produces a short, translucent stem with one to four nodding flowers. Each flower is about 1.5 to 2 cm in size, with pale yellow sepals and petals that can have pink or purple markings. The flower is non-resupinate, meaning its lip and a prominent spur point upwards, an unusual orientation for an orchid.
Pollination is also a rare event. The flowers are thought to be pollinated by bumblebees, which are attracted to a faint scent sometimes described as being like bananas or vanilla. The plant produces very little seed, and its appearances are so sporadic that populations can go unrecorded for long periods. In the United Kingdom, one population reappeared after a 54-year absence. The entire above-ground phase, from the stem emerging to the seeds maturing, lasts only a few weeks before the plant vanishes back into the leaf litter.