Gymnadenia conopsea - Chalk Fragrant-orchid

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

Above: Chalk Fragrant-orchid, Minera Quarry, Wales UK

The Fragrant-orchids have been the subject of much molecular study in recent years, and as a result of differences revealed between them, the three British-growing varieties currently recognised as Gymnadenia conopsea (Chalk Fragrant-orchid), Gymnadenia borealis (Heath Fragrant-orchid) and Gymnadenia densiflora (Marsh Fragrant-orchid) are now designated as three distinct species. The third of these species, Marsh Fragrant-orchid, grows in alkaline marshy ground and is therefore more easily distinguishable by habitat if not by obvious morphological differences. The remaining types, Chalk Fragrant-orchid and Heath Fragrant-orchid are more difficult to tell apart.

Description

Normally growing to a height of around 40cm, exceptionally to 60cm, this orchid has 3-6 narrow pointed basal leaves. There are also a few smaller bracts higher on the stem but beneath the flowers.

The inflorescence is cylindrical and much narrower than those of the Pyramidal Orchid Anacamptis pyramidalis with which this orchid is sometimes confused. Each plant can carry up to 200 individual flowers which are usually mauve rather than pink or purple and have broad lips. Occasionally pure white flowers appear within ccolonies of mauve Chalk Fragrant-orchids.

The flowers have an instense perfume which is particularly noticeable in the evening or early morning.

Distribution

This orchid is well distributed throughout Europe and into eastern Asia, China and the Himalayas but they are rarely found in the Mediterranean zone. In the Alpine dry meadows of Slovenia the Chalk Fragrant-orchid grows alongside Gymnadenia odoratissima, offering a unique opportunity to make comparisons between the two species.

In Wales and other parts of the UK they are particularly numerous in coastal dune slacks, a habitat rich in chalk due to the high content of crushed sea shells present there. Two excellent places to see the Chalk Fragrant-orchid are Kenfig National Nature Reserve in South Wales, and Newborough Warren National Nature Reserve in Anglesey in North Wales. In Ireland The Burren is an outstanding place to see these lovely orchids.

Above: Chalk Fragrant-orchids and Common Spotted-orchids in limestone grassland, North Wales

Flowering times

Mid-May to July, with June being the peak flowering period in Britain and Ireland.

Hybrids and Varieties

Varieties
var. albiflora has white flowers
var. crenulata has broad lobes on the lip
.
Hybrids
Britain's three species of Fragrant-orchids may hybridise, but confirmation of this is difficult.

Intergeneric Hybrids
X Gymnanacamptis anacamptis with Pyramidal Orchid Anacamptis pyramidalis
X Gymnaglossum jacksonii with the Frog Orchid Dactylorhiza viridis
X Dactylodenia heinzeliana with Common Spotted-orchid Dactylorhiza fuchsii
X Dactylodenia legrandiana with Heath Spotted-orchid Dactylorhiza maculata
X Dactylodenia wintoni with Southern Marsh-orchid Dactylorhiza praetermissa.

Etymology

The genus name Gymnadenia means 'naked gland' and refers to the characteristics of the flower spur within which nectar is secreted. The specific epithet conopsea means 'mosquito-like' and may refer to the long flower spur which resembles the elongated mouthparts of a mosquito.

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

Den Nordiska Floran (1992) Bo Mossberg, Stefan Ericsson and Lennart Stenberg; Wahlstrom & Widstrand