Dactylorhiza praetermissa Southern Marsh-orchid: identification, distribution, pictures

The Southern Marsh-orchid is tolerant of a wide range of predominantly alkaline habitats, but occasionally it strays into mildly acidic parts of bogs and damp heaths. Best known in the south and often found on riversides and in damp meadows, this orchid also grows in abandoned quarries, on roadside verges and in some old industrial sites; in suitable places it can occur in large numbers. Dactylorhiza praetermissa is extremely variable in appearance and readily hybridises with spotted orchids, causing much confusion during identification. A 'typical' plant would be a robust, thick-stemmed orchid with broad unmarked leaves and relatively large pink-to-purple flowers. It is worth bearing in mind, however, that very small plants can also occur in drier marginal habitats such as chalk grassland. In Britain and Ireland, the Southern Marsh-orchid flowers between mid May and mid July. This species is endemic to Europe, and on the mainland it can be found in Scandinavia, northern France and southwards as far as northern Italy.

Distribution Map		Key Features
	Records for the Southern Marsh-orchid from BSBI are shown on the map with most recent in front. (Hover the mouse over the small map to expand it.) CLICK HERE to visit the BSBI website page for updated data and maps with separated data for individual record periods.	Plant: 20 to 70cm tall, but the larger plants may be due to hybridisation with other species. The stem is markedly stout, green and hollow. Leaves: up to 9 flat sheathing leaves, which are greyish-green and unmarked and which vary greatly in width. There are also up to 3 narrower and more pointed leaves higher on the stem. Bracts: green, washed purple. Flowers: pink to purple; normally between 20 and 60 on a single inflorescence but up to 100 on very large plants. The upper sepal and petals form a loose hood over the lip, which is broad and almost circular, shallowly tri-lobed, with broad and rounded lateral lobes that often appear 'folded backwards' and a small, pointed central lobe. The lip is mainly pink, becoming white towards the base, and its centre is finely marked with dots and dashes.

Image Gallery for Southern Marsh-orchid Dactylorhiza praetermissa

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Title of album Description of album
Title of album Description of album

Pollination

Taxonomy & Hybrids

The Southern Marsh-orchid is pollinated by a variety of insects, and seed set is good. Plants may also reproduce vegetatively.

The specific name praetermissa means 'overlooked' - a reference to the fact that it was not recognised until 1914.

Subspecies: none.
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.

Articles about Southern Marsh-orchid in JHOS