Epipogium aphyllum

The Epipogium aphyllum, popularly known as the Ghost Orchid, is a herbaceous terrestrial vascular plant belonging to the orchid family (Orchidaceae). It is renowned for its unusual behavior: it is a mycoheterotrophic plant, meaning it lacks chlorophyll and does not perform photosynthesis. It earns the name "ghost orchid" precisely because of its pale, translucent appearance and the fact that it spends most of its life hidden underground, emerging only during its highly unpredictable flowering period, which does not occur every year.

Morphological description: Due to the absence of chlorophyll, the plant exhibits a whitish, yellowish, or reddish translucent coloration. The stem, measuring between 8 and 25 cm in height, is slender, hairless, and has a thickened base. Its leaves are practically absent, reduced to small scales or membranous sheaths. The inflorescence can bear 1 to 8 flowers (exceptionally up to 10), widely spaced. The flowers are distinctive because their main petal (the labellum) is positioned at the top, inverted compared to most orchids (a non-resupinate flower). They are creamy or yellowish in tone, with a white labellum adorned with pink or purple spots, ridges, or papillae, and feature a thick, sac-shaped spur directed upwards. Underground, it possesses a thick rhizome, without true roots, from which slender stolons emerge.

Ecology and life cycle: Pollination is entomophilous, primarily carried out by bumblebees and flies, such as Bombus hortorum, Bombus lucorum, Bombus pascuorum, and Musca corvina. These insects are attracted by the flower's sweet fragrance, often described as a fermented banana scent, although seed production and fruiting are exceptionally rare. Its life cycle is entirely dependent on a symbiotic association (mycorrhizal network) with soil fungi (basidiomycetes, such as the genera Inocybe or Hebeloma), from which it extracts all essential nutrients. Since it produces few seeds, it typically reproduces vegetatively through its underground stoloniferous structures, which can make the plant appear to "shift" its location each year. Flowering is "capricious" and requires very specific conditions, generally springs and summers with abundant rainfall, occurring in July and August; if the environment is dry, flowering can abort underground or even occur hidden beneath the leaf litter.

Habitat and distribution: It inhabits old, humid forests with soils rich in organic matter, especially in areas of deep shade. In our region, it almost always develops in the dark understory of beech and fir forests, growing directly from leaf litter or decomposing humus. It prefers locations that experience cold winters. Globally, it has an extremely wide Eurasian distribution (from Western Europe to Japan, Kamchatka, and the Himalayas), yet it is excepcionally rare wherever it grows. In the Iberian Peninsula, it is found very isolated, mainly in the Pyrenees and nearby areas (such as Catalonia: Vallespir, Pallars Sobirà, Alta Ribagorça, Berguedà, and Montseny; or La Rioja, Navarre, and Huesca). It is absent from the strict Mediterranean region.

Conservation status: On a global European scale, the IUCN classifies it as "Least Concern" (LC) given its wide territorial distribution, but in practical terms, it is considered extremely scarce in its habitats and is strictly protected in nearly 56 countries. In Spain and Catalonia, it is considered one of the rarest plants; in the Catalonian Catalogue of Threatened Flora, it is listed as "Endangered". It is primarily threatened by the degradation of its primary forest habitat, changes in humidity caused by drought, timber harvesting practices that clear forests, incursions by wild boars that devour its rhizomes, and accidental damage (trampling) by enthusiasts and photographers.