Epipactis, or Helleborine, is a genus of terrestrial orchids consisting of approximately 70 species. This genus is abbreviated as Epcts in horticultural trade.
The species occur in temperate and subtropical climates of America, Asia, and Europe. These orchids grow in open spaces in forests, in undergrowth, on calcareous soils and are often found in wet dune-slacks near the sea. The only original American species is Giant Helleborine (Epipactis gigantea). One species from Europe, Broad-leaved Helleborine (Epipactis helleborine), is invasive in North America. Most species are protected.Marsh Helleborine
Most of these hardy orchids grow in a wet environment, but there are exceptions. The Marsh helleborine (Epipactis palustris) is the only European orchid able to survive in a flooded habitat. Epipactis gigantea is a species found in the American west, and into southern Canada, in wet areas and even streams. It can grow to a height of 1 m. However, Epipactis helleborine grows in more diverse habitats, from sheltered sandy beaches to open spaces in deciduous or coniferous forests, on roadsides, in meadows, and on moist soils. It is sometimes called the Weed Orchid.
As characteristic of all orchids, Epipactis spp. are dependent on a mycorrhizal symbiosis (see also Orchid mycorrhiza). This allows some species to have reduced leaves and need little chlorophyll. Violet Helleborine (Epipactis viridiflora) can even do without chlorophyll. These forms can be recognized by their purple instead of violet flowers.
Their creeping, fleshy rhizomes grow offshoots, from which then emerge the 20–70 cm long stems during the next spring.
Their bilaterally symmetrical colorful flowers grow from a terminal raceme. The three sepals and the two lateral petals are ovate and acuminate. Their color can vary from greenish-white to violet and purple.
The lip is divided in a bowl-shaped hypochile, with the outer surface greenish-white and threaded with dark veins. The wavy, snow-white epichile is fan-shaped.