Dactylorhiza majalis, or the broad-leaved marsh orchid, is a terrestrial Eurasian orchid. Subspecies include the western marsh orchid (Dactylorhiza majalis subsp. occidentalis) and southern marsh orchid (Dactylorhiza majalis subsp. praetermissa). The broad-leaved 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

On average, Dactylorhiza majalis is 15 to 40 cm tall, though specimens can grow up to 60 cm. Four to ten spotted leaves (either purple or burgundy in color) are distributed around the stem, which is hollow. The leaves are ovate to lanceolate and 6 to 18 cm long by 1.5 to 3.5 cm wide, and get smaller and more lanceolate as they approach the inflorescence. The bracts are about as long as the blossom and cover it before it blooms. The densely flowered inflorescence, which is approximately 5 to 15 cm long, is initially conical, but distinctly cylindrical when in full blossom. The seven to fifty blossoms are colored purplish red, rarely light pink or white. The tuber has a palmate division and an irregular shape. The broad-leaved marsh orchid has a karyotype of four sets of twenty chromosomes (2n = 4x = 80) and a genome size of 14.24 Gbp (2C). 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).

Taxonomy

In 1828 Ludwig Reichenbach described the broad-leaved 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:

Subspecies and varieties

Many names have been proposed at the subspecies, variety and form levels. As of August 2024 15 subspecies are accepted.

Hybrids

Hybrids between subspecies include: The broad-leaved marsh orchid hybridizes quite commonly with other species of its genus. Some inter-species hybrids include: More rarely, hybrids with other genera (intergeneric hybrids) occur.

Formerly placed here

Range

Dactylorhiza majalis is widespread across much of Europe and north-central Asia, from Spain and Ireland to Siberia and Kazakhstan. In Germany the broad-leaved marsh orchid is widespread but with several gaps. In many places, especially from western to northern Germany, it is extinct. In Switzerland it is also quite widespread. A significant gap is found south of the Aar between Aarau and Lake Neuchâtel.

Conservation

Although the broad-leaved 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 broad-leaved 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.