User:Louis.Hight/Epipactis helleborine

Epipactis helleborine is a terrestrial species of orchid that is morphologically diverse but identifiable by its star-shaped flowers. It originated in the

Old World but is naturalized in North America.

Description
Epipactis helleborine varies in flower morphology and nutritional mode and is rhizomatous. Roots are thick and grow in dense masses. Some plants are photoautotrophic and partially myco-heterotrophic to varying degrees while others are completely mycohetertrophic. E. helleborine also has a wide range of height variation, growing to a height of between 15 centimeters to one meter. Chlorophyl-free, mycohetertrophic orchids may be smaller than photosynthetic orchids.

Leaves are broad, ribbed, and flat. Leaves and stems of fully myco-heterotrophic E. helleborine are white, and the color of partially myco-heterotrophic plants ranges from yellow-ish green to dark green depending on the level of chlorophyll deficiency. E. helleborine may also have variegated leaves.

Star-shaped, greenish white flowers with labella that may be partly rose, brownish, or red grow on spear-shaped bracts that are longer towards the base of the plant than at the top. Flower number may be between 30 and 50 and is variable between populations. Lateral sepals are mostly oval in shape, and the dorsal sepal is elliptical and slightly larger. The size of the sepals varies between regions where E. helleborine is found.

In the United States, E. helleborine blooms in the summer, and the blooming seasons are longer in areas with a greater number of plants. The orchid may reproduce through pollination and germination but more commonly spreads through rhizomatous, clonal growth.

Distribution
Epipactis helleborine is widespread across Europe and Asia, where its range stretches as far north as Scandinavia and Siberia down to northern Africa and the Himalayas and from Portugal to Japan   It was found growing in the United States for the first time in 1879 after being introduced by uncertain means. Since its discovery in the United States, it has spread throughout the country and into Canada. In its non-native range in North America it may be considered invasive.

Habitat
Epipactis helleborine is often found in woodland areas and in hedge-banks. It grows in forested areas of various types of trees depending on region. For example, it is commonly found near pine forests in Japan and near cottonwoods, willows, and other trees of the cottonwood forests along the Rio Grande. It is also known for its colonization of anthropogenic habitats including parks, roadsides, quarries, and gravel pits, with many sites in Glasgow, London, and Moscow for example. E. helleborine can live in low to bright light conditions. This orchid species has adapted to multiple niches and has spread rapidly in areas where it has been naturalized, particularly in soils rich in calcium.

Pollination
Epipactis helleborine relies on insects for pollination and is commonly pollinated by insects from the families Apidae, Culicidae, Formicidae, and Syrphidae. Some populations of E. helleborine are opportunistic regarding pollinators while others are adapted to be pollinated by insects with specific mouth types. Insects are attracted to nectar secreted by the orchid, and eight populations in central Europe were found to produce nectar containing opioid compounds including oxycodone which may have an intoxicating effect on insects. E. helleborine in dry habitats may also achieve pollination through selfing.

Mycorrhizal Associations
E. helleborine forms symbiotic relationships with mycorrhizal fungi for its entire life cycle. Germination requires mycorrhizal fungal symbionts that provide the dust seeds of the orchid with nutrients, allowing them to develop. Adult orchids may be partially or completely myco-heterotrophic.

Over its global range, E. helleborine has been documented associating with several fungi of genera Hydnotrya, Leptodontidium, Peziza, Tuber, and Wilcoxina. Locally, there is evidence that fungal selection by E. helleborine may be highly specific. Because Wilcoxina also forms associations with pine trees, it has been speculated that when E. helleborine forms a symbiotic association with Wilcoxina fungi, the orchid may obtain carbon from pine trees through the fungi. E. helleborine can survive off of the nutrients provided by its mycorrhizal fungi for over a year and, therefore, does not have to grow above ground every year.

Subspecies (unchanged from current page)
A rather long list of names have been proposed for subspecies, varieties and forms of Epipactis helleborine, far too many to list here. This is not unusual for such a widespread species. At present (November 2021) only the following are accorded international acceptance:


 * 1) Epipactis helleborine subsp. bithynica (Robatsch) Kreutz - Turkey
 * 2) Epipactis helleborine subsp. helleborine - widespread
 * 3) Epipactis helleborine subsp. neerlandica (Verm.) Buttler - Great Britain, Norway, Denmark, Belgium, Netherlands, France, Germany
 * 4) Epipactis helleborine var. tangutica (Schltr.) S.C.Chen & G.H.Zhu - China
 * 5) Epipactis helleborine subsp. tremolsii (Pau) E.Klein - France, Spain, Portugal, Sardinia, Italy, Algeria, Morocco