Dactylorhiza majalis

Dactylorhiza majalis
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Monocots
Order:	Asparagales
Family:	Orchidaceae
Tribe:	Orchideae
Genus:	Dactylorhiza
Species:	D. majalis
Binomial name
Dactylorhiza majalis (Rchb.) P.F. Hunt & Summerh.

Dactylorhiza majalis (western marsh orchid, broad-leaved marsh orchid, fan orchid, common marsh orchid, or Irish marsh orchid) is a terrestrial Eurasian orchid.^{[1][2][3][4][5]}

The western marsh orchid grows mainly in nitrogen-poor marsh areas that consist of several plant communities. More rarely, it is found in fens. Its flowering period begins at lower elevations as early as the beginning of May and ends in higher elevations at the end of July. The lowest blossoms usually open even before the stem has reached its full height.

Description

Detail of inflorescence

The western marsh orchid is usually 15 to 40 cm (6 to 15.5 in) tall, though some specimens may reach 60 cm (2.0 ft). Three to eight dark spotted leaves are distributed on the stem, which is hollow. The lower leaves are ovate to lanceolate and 6 to 18 cm (2.5 to 7 in) long and 1.5 to 3.5 cm (⅝ to 1⅜ in) wide. The upper leaves are increasingly smaller and more lanceolate. The bracts are about as long as the blossom and cover it before it blooms. The densely flowered inflorescence, which is 4 to 15 cm (1.5 to 6 in) long, is at first conical, but distinctly cylindrical when in full blossom. The seven to forty blossoms are colored purplish red, rarely light pink or white. The lateral tepals of the external circle of the perianth stand obliquely or vertically upright. They are 7 to 12 mm (¼ to ½ in) long and 2.5 to 5 mm (⅛ to ³⁄₁₆ in) wide. The middle tepal is smaller and forms a "helmet" together with the two lateral tepals of the internal circle. These are 6 to 11 mm (¼ to ⁷⁄₁₆ in) long. The trilobate lip is 5 to 10 mm (³⁄₁₆ to ⅜ in) long and 7 to 14 mm (¼ to ⁹⁄₁₆ in) wide. The shape and pattern of the lips are variable. In the lighter central area of the lip the markings are made up of lines, streaks, or dots. The spur is bent slightly downwards and is not quite as long as the ovary. The tuber has a palmate division and an irregular shape.

The western marsh orchid has a karyotype of two sets of forty chromosomes. The seed of this orchid contains no endosperm for the embryo. Therefore, germination can take place only by means of infection with a root fungus (mycorrhiza).

The western marsh orchid in a damp forest meadow in Baden-Württemberg, Germany.

Taxonomy

In 1828 Ludwig Reichenbach described the western marsh orchid as Orchis majalis. The name became the basionym after Peter Francis Hunt and Victor Samuel Summerhayes transferred the species to the genus Dactylorhiza in 1965. Sometimes the name Dactylorhiza fistulosa is used, but since this description is not valid, the name cannot be used despite its earlier publication in 1794 as Orchis fistulosa.

Many synonyms have been published:^[6]

Subspecies, varieties and hybrids

Dactylorhiza × aschersoniana

Dactylorhiza × braunii

• Subspecies and varieties

Many names have been proposed at the subspecies, variety and form levels, but as of June 2014 only the following are recognized:^[6]

• Dactylorhiza majalis subsp. baltica (Klinge) H.Sund. – Finland, Germany, the Baltic Republics, Russia, Siberia, Kazakhstan
• Dactylorhiza majalis subsp. ebudensis (Wief. ex R.M.Bateman & Denholm) M.R.Lowe – Outer Hebrides of Scotland
• Dactylorhiza majalis var. francis-drucei (Wilmott) R.M.Bateman & Denholm – Scotland
• Dactylorhiza majalis var. kerryensis (Wilmott) R.M.Bateman & Denholm – western Ireland
• Dactylorhiza majalis subsp. majalis – widespread across much of Europe from Spain to Russia
• Dactylorhiza majalis subsp. occidentalis (Pugsley) P.D.Sell – Britain and Ireland
• Dactylorhiza majalis subsp. sphagnicola (Höppner) H.A.Pedersen & Hedrén – Scandinavia, Germany, France, Belgium, Netherlands
• Dactylorhiza majalis subsp. traunsteinerioides (Pugsley) R.M.Bateman & Denholm – Britain and Ireland

The western marsh orchid hybridizes quite commonly with other species of its genus.

• Dactylorhiza × aschersoniana (Dactylorhiza incarnata × D. majalis)
• Dactylorhiza × braunii (Dactylorhiza fuchsii × D. majalis)
• Dactylorhiza × dufftiana (Dactylorhiza traunsteineri × D. majalis)
• Dactylorhiza × godferyana (Dactylorhiza praetermissa × D. majalis)
• Dactylorhiza × kuehnensis (Dactylorhiza ruthei × D. majalis)
• Dactylorhiza × townsendiana (Dactylorhiza maculata × D. majalis)
• Dactylorhiza × rupertii (Dactylorhiza sambucina × D. majalis)

More rarely, hybrids with other genera (intergeneric hybrids) occur.

• ×Dactyloglossum drucei (Coeloglossum viride × Dactylorhiza majalis)
• ×Dactylodenia lebrunii (Dactylorhiza majalis × Gymnadenia conopsea)

Range

Dactylorhiza majalis is widespread across much of Europe and north-central Asia from Spain and Ireland to Siberia and Kazakhstan.^[6]

In Germany the western marsh orchid is widespread but with several gaps. In many places, especially from western to northern Germany, it is extinct.

In Switzerland the western marsh orchid is also quite widespread. A significant gap is found south of the Aar between Aarau and Lake Neuchâtel.

Conservation

Although the western marsh orchid is commonly found in some regions, it is nevertheless protected as an orchid.

As with many marsh plants, the numbers of this species have been dwindling for quite some time. The main causes are the entry of nitrogen via fertilizer, drying out of the habitat, and intensive conversion to pasture. The western marsh orchid does not react so sensitively to changes in its habitat as for example the early marsh orchid, Dactylorhiza incarnata. It is usually the last of the native orchids to disappear. This tolerance makes it a still relatively common species.

References

This article incorporates text translated from the corresponding German and French Wikipedia articles as of 4 February 2006.

External links

• Media related to Dactylorhiza majalis at Wikimedia Commons
• Dactylorhiza majalis at the Encyclopedia of Life
  
• Den virtuella floran Distribution

Orchid of the Year in Germany
Western marsh orchid (1989) Pyramidal orchid (1990) Green-winged orchid (1991) Common twayblade (1992) Military orchid (1993) Fen orchid (1994) Bee orchid (1995) Lady's-slipper orchid (1996) Bug orchid (1997) Marsh helleborine (1998) Lizard orchid (1999) Red helleborine (2000) Autumn lady's-tresses (2001) Bird's-nest orchid (2002) Fly orchid (2003) Frog orchid (2004) Burnt orchid (2005) Broad-leaved helleborine (2006) Nigritella nigra subsp. rhellicani (2007) Southern marsh orchid (2008) Early purple orchid (2009) Lady's-slipper orchid (2010) Lesser butterfly orchid (2011) Orchis pallens (2012) Lady orchid (2013) Ghost orchid (2014) Early marsh orchid (2015) Summer lady's-tresses (2016) White helleborine (2017)