Orchids of the British Isles - Bogs, Fens and Marshes Content from the guide to life, the universe and everything

Orchids of the British Isles - Bogs, Fens and Marshes

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The shield of the Science, Mathematics and Engineering faculty of the h2g2 University.Orchids of the British Isles - Introduction
Animal Nomenclature | Orchids of Bogs, Fens and Marshes | Dactylorhiza | Helleborines (Cephalanthera) | Helleborines (Epipactis) | Insect Mimics
Lady's Slipper Orchid | Miscellaneous Orchids | Orchis | Saprophytes | Tresses | Twayblades

This group of orchids are not related, but they do share a common theme. They all grow on marshland.

Fen Orchid Liparis loeselii and Liparis ovata

This orchid was for a long time considered totally British, existing nowhere else in the world, but it has recently been discovered growing in the north-west of France.

There are two forms of this orchid - Liparis loeselii and Liparis ovata. Both grow in two different habitats, but they both need damp areas to survive.

The fen orchid has large fleshy leaves, which are much longer than they are broad. Two bright yellow-green leaves protect the pseudobulb1 at the base of the stem; from the centre a flower stem reaching up to 20cm emerges. The flowers, up to 18 in total, are held close to the stem and are shiny yellow-green in colour. The four outer petals are long and narrow, looking almost like spurs, while the other two petals form a small hood and lip, which turns up at the side to form a gutter. The flowers have no scent or nectar, so do not attract any pollinating insects.

Pollination is mostly assisted by the rain. When raindrops hit the small hood, which is hinged, they bang down onto the pollinia which in turn pushes pollen onto the stigma.

This orchid grows, as its name suggests, on fenland and is restricted to three small sites in Norfolk. It likes to occupy the edges of pools, where vegetation is sparse or in its early stages of colonisation.

The fen orchid is under threat from loss of habitat. Over many years drainage work and lowering of the water table, has wiped out many colonies. The remaining areas where this orchid grow are now under management, to ensure that the colonies can survive and hopefully multiply.

Liparis ovata

Liparis ovata has no common name. It grows on wet coastal dune slacks. To survive this particular orchid needs a constant succession of new dune slacks. This is because as a dune slack becomes old it dries out and cannot sustain the orchid.

The leaves of this orchid are smaller and more compact than the fen orchid. Its flowers, which are the same as the fen orchid, are much smaller, each stem only carrying three to six flowers.

Bog Orchid Hammarbya paludosa

This rare orchid is tiny, only growing 3-12cm in height. It grows from a pseudobulb which is just above ground. Each year the orchid produces a new pseudobulb next to the one from the previous year, which will eventually die. The leaves are yellow-green and oval in shape. The upper leaves sometimes have little bulbils2 around their edges, which break off and float away to form a new orchid somewhere else.

The flowers are small and also yellow-green in colour. The three outer petals fold right back and wrap around the stem of the flower, while the bottom petal is held just out from the stem. The other two petals form a lip, which always points upwards. This is unusual in orchids as most of them have the lip held downwards. The lip is pointed and marked with two shades of green stripes. The nectar is produced in the base of the lip and has a faint smell of cucumber.

Pollination is done by the gnat Sciara thomae and also by other small flies which are common around bogs.

This orchid likes to grow in areas of established sphagnum moss, where the water remains acidic. It is often found growing on floating carpets of moss and occasionally in running shallow water on stony areas.

The decline of this orchid is mostly due to the draining of bogs, especially in southern England, though it can still be found in areas of Devon, Dorset, Hampshire and a few places in Scotland.

Marsh Hellebore Epipactis palustris

This is one of the most beautiful of the British orchids. Its flowers are striking and bear a resemblance to the tropical Cymbidium in appearance. It grows up to 60cm in height, with long ovate leaves folded down the centre with three marked veins. It has an extensive root system which creeps underground and can multiply from the rhizomes it forms.

There are two distinct forms of this orchid Epipactis palustris, with pink flowers, and Epipactis ochroleuca, which has white flowers. There are up to 20 flowers produced on a stem. Each flower is held out from the main stem and hangs like a bell. In the pink form, the outer three sepals are purplish-brown and pointed. When looked at face-on, they form a triangle shape. The top two petals are white, tingled with pink, and are placed either side of the top sepal. The lip is divided into two parts. The innermost part is formed into a small cup, and is white with deep pink veins. From the outer edge of the cup a pointed lip is attached; it is white in colour and has a frilled edge. Across the centre of the lip is a yellow plate, which guides insects to the centre of the flower.

The white form of this orchid has the same flowers, but lacks the purplish-brown and pink colours. Its outer sepals are greenish-yellow and the rest of the flower is white.

It's not clear which insects pollinate this orchid, but it is thought ants play a big role by disturbing the pollen sacs while looking for food. The pollen then falls onto the stigma, which pollinates the plant.

The two variants of this orchid like to grow in fens, marshes or wet meadows. They are also found in dune slacks where plenty of lime is present. In 1983 one plant was discovered in the Central Highlands, where this orchid is very rare.

The decline of this species in recent years, has been due to very dry summers where its habitat has dried out, though most sites were lost pre-1930 with the drainage of marshland

1A bulb-like swelling of the aerial stem, and is not a true bulb.2A small bulb growing on the edge of a leaf or between the leaf and stem of a plant.

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