Dactylorhiza praetermissa - Southern Marsh-orchid

Phylum: Magnoliophyta - Class: Liliopsida - Order: Orchidales - Family: Orchidaceae

Above: Dactylorhiza praetermissa in Kenfig NatureReserve in South Wales, in late spring.

Notoriously difficult to identify with confidence, this orchid is widespread within its range and it can form large colonies when growing in ideal habitats.

Description

The Southern Marsh-orchid typically grows to between 30and 50cm in height, although taller specimens up to 70 cmcan occur. The leaves are generally unmarked, and the flowers vary considerably in colour from dark pink to a much paler pink; the markings on the lips of the flowers also vary considerably.

Difficult to distinguish from, among others, the NorthernMarsh-orchid Dactylorhiza purpurella, the lip of the Southern Marsh-orchid isgently rounded and slightly folded back; its flowers are generally larger, and the lip of the Northern Marsh-orchid ismore angular. Southern Marsh-orchid is also confused with Early Marsh-orchid Dactylorhiza incarnata and they frequently occur in the same habitats. To add to the confusion Southern Marsh-orchid also hybridises with other Dactylorizha species, and hybrids between Dactylorhiza praetermissa and Dactylorizha fuchsii (Common Spotted-orchid) are most often revealed by their faintly spotted leaves.

A pale pink-flowered example of the Southern Marsh-orchid

Distribution

Southern Marsh-orchid is widely distributed in the southern half of the UK. In mainland Europe is it confined to the more northern countries with an Atlantic coastline.

Habitat

Southern Marsh-orchid is a chalk-loving species and grows in damp alkaline meadows and in sand dune slacks in full sunshine. Although often thought of as a coastal species, Southern Marsh-orchid does grow inland too and can be found in damp meadows and on river banks thoughout its range. In Wales, for instance, Southern Marsh-orchid is a special feature of the Elan Valley Estate, where it grows in riverside grassland and other wet meadows.

Flowering times

Southern Marsh-orchids flower from late May until the end of July.

Hybrids and Varieties

Varieties:
Dactylorhiza praetermissa var. albiflora has white flowers and is rare.
Dactylorhiza praetermissa var. macrantha has large flowers on a lax spike and its flower lips have a larger central lobe; it is found with Narrow-leaved Marsh-orchid Dactylorhiza traunsteinerioides and could be an intermediate between the two species.
Dactylorhiza praetermissa var. bowmanii is a slender plant with narrower and fewer leaves and is sometimes confused with Narrow-leaved Marsh-orchid Dactylorhiza traunsteineriodes; it has been reported from Hampshire and Dorset.
Hybrids:
Dactylorhiza x grandis is a hybrid with the Common Spotted-orchid Dactylorhiza fuchsii; it is common.
Dactylorhiza x insignis is a hybrid with Northern Marsh-orchid Dactylorhiza purpurella and is recorded in Wales.
Dactylorhiza x wintoni is a hybrid with Early Marsh-orchid Dactylorhiza incarnata;it is rare.
Dactylorhiza x hallii is a hybrid with Heath Spotted-orchid Dactylorhiza maculata and is much less common than Dactylorhiza x grandis, the hybrid with Common Spotted-orchid.

Etymology

The genus name Dactylorhiza means 'finger-like roots', while the specific epithet praetermissa means 'neglected', in the sense of overlooked.

Reference sources

The Plant List

Sue Parker (2023) Wild Orchids of Wales - how, when and where to find them; First Nature e-book (Amazon Kindle format)

Anne and Simon Harrap (2005) Orchids of Britain and Ireland; A&C Black

Pierre Delforge (2005) Orchids of Europe, North Africa and the Middle East; A&C Black