Common Spotted Orchid (Dactylorhiza fuchsii)
Found throughout temperate Europe, the Common Spotted orchid (Dactylorhiza fuchsii) reaches up to 70 cm in height. The stem is pale green and sometimes washed purple towards the tip (due to anthocyanin), grooved and is usually solid. The leaves are green and usually decorated by solid dark spots and blotches but are sometimes unmarked. These dark spots of anthocyanin pigmentation on the leaves give this orchid its common name. There is a small oval and blunt-tipped (obtuse) basal leaf and 3 to 6 (occasionally 2 or 7) sheathing leaves above the basal leaf. There are 2 to 6 (1 to 9) narrower stem leaves which become bract-like towards the flowering spike. Each flower is subtended by a bract, which is green (sometimes washed purple) narrow and pointed (lanceolate) and as long as or longer than the ovary of the flower (the bracts are generally shorter and about equal to the ovary in length higher up the spike).
The ovary is green (sometimes with a violet tinge), cylindrical, twisted and has six ribs. The petals and sepals vary in color from pale lilac, pink, purplish-pink or almost white. The upper sepal and the two petals form the hood. The labellum (third petal) is oval, 8 to 12 mm wide and has three lobes separated by deep sinuses - the lobes separate the labellum about midway along its length. The lateral lobes have broad rounded tips and may be toothed and are usually slightly depressed. The central lobe is triangular. The labellum is whitish with dark red or purple dashes forming concentric double loops. The lateral sepals may bear red or purple lines and spots. The spur varies from about half as long to as long as the ovary and is narrow, more-or-less straight and cylindrical or tapering. The pollinia vary from pale brown to pink/purple or yellowish. the flowers produce a faint scent.
The flowers are pollinated by beetles, such as longhorn beetles and other insects. The spur produces no apparent nectar. It has been hypothesised that the spur has sugary sap in its inner wall. There are also sugar-rich papillae on the central region of the lip (do these extend to the spur?). Honeybees possibly access sugary fluid on the stigma. Certainly it is rare to see a common spotted orchid in full bloom not attracting a number of insects, whether or not these are affecting pollination. I have seen the predominant insect type visiting the flowers vary over time throughout the season. Pollination is efficient: typically 50 to 90% of flowers are pollinated.
Dactylorhiza fuchsii occurs in a wide range of habitats, from dry grassland to wet meadows, machair, marshes, fens, dune slacks, woodland (especially the brighter lit parts) on a range of soils from alkaline to slightly acidic, including gravel, chalk pits and waste sites.
Two forms or subspecies are recognised: ssp. fuchsii is the most common, and the one shown here, whilst ssp. hebridensis is found in the Hebrides, the Shetlands and northwest Scotland and is on average a shorter plant (up to 20 cm). Several varieties are also recognised: var. alpina has dark flowers and occurs in northern Britain and may be found with ssp. hebridensis. Var. albiflora lacks anthocyanin and so has no dark spots on the leaves and unmarked white flowers; var. cornubiensis (Cornish or Hebridean Common Spotted) is similar to ssp. hebridensis but has a narrower lip; var. okellyi has narrow leaves and almost white flowers (it has a small amount of anthocyanin) and var. rhodochila is a rare variety with a high anthocyanin content (it is hyperchromatic) in the flowers, stem and leaves, giving the flowers a deep purple color. External link: a study of color variations in Common Spotted Orchid in Ireland
Above: var. okellyi with almost white flowers (there are a few small purple spots of anthocyanin so this is not var. albiflora), note the narrow spotted leaves.
