About Dactylorhiza majalis subsp. purpurella (T.Stephenson & T.A.Stephenson) D.M.Moore & Soó
Dactylorhiza majalis subsp. purpurella, the broad-leaved marsh orchid, is an orchid with an average height of 15 to 40 cm (6 to 15+1⁄2 inches); some individual plants can reach up to 60 cm (2.0 ft) tall. It has a hollow stem, with four to ten purple or burgundy spotted leaves arranged around it. Leaves range in shape from ovate to lanceolate, and measure 6 to 18 cm (2+1⁄2 to 7 in) long by 1.5 to 3.5 cm (1⁄2 to 1+1⁄2 in) wide. Leaves grow smaller and more narrowly lanceolate closer to the inflorescence. Bracts are roughly the same length as the flower buds and cover the buds before the plant blooms. The densely flowered inflorescence is 5 to 15 cm (2 to 6 in) long, starting conical in shape before becoming distinctly cylindrical when fully open. Each inflorescence holds seven to fifty purplish red flowers; light pink or white flowers are rare. The lateral outer tepals of the perianth are positioned obliquely or vertically upright, and measure 7 to 12 mm (1⁄4 to 1⁄2 in) long by 2.5 to 5 mm (1⁄8 to 3⁄16 in) wide. The middle outer tepal is smaller, and forms a "helmet" shape with the two inner lateral tepals, which are 6 to 11 mm (1⁄4 to 7⁄16 in) long. The trilobate lip of the flower is 5 to 10 mm (3⁄16 to 3⁄8 in) long and 7 to 14 mm (1⁄4 to 9⁄16 in) wide. Lip shape and patterning are variable, with markings of lines, streaks, or dots in the lighter central area of the lip. The spur is slightly bent downward, and is slightly shorter than the ovary. The orchid's tuber is irregularly shaped and palmately divided. The broad-leaved marsh orchid has a karyotype of four sets of twenty chromosomes (2n = 4x = 80), with a 2C genome size of 14.24 Gbp. Its seeds do not contain endosperm to support the embryo, so germination can only occur when the seed is infected by a root mycorrhizal fungus. Dactylorhiza majalis is widespread across most of Europe and north-central Asia, ranging from Spain and Ireland east to Siberia and Kazakhstan. In Germany, it is widespread but has multiple gaps in its distribution, and is extinct in many areas, particularly from western to northern Germany. In Switzerland, it is also fairly widespread, with a notable distribution gap south of the Aar river, between Aarau and Lake Neuchâtel.
