|Caithness Field Club|
Most people are familiar with two common orchids locally. The Heath Spotted Orchid (Dactylorhiza maculata ericetorum) has narrow leaves with fine round purple spots and a flower of white to pale purple with darker purple lip markings. It is useful to get to know the shape of this lower lip since it is a useful pointer to the identity of orchids. In this case the lower lip is large and round with a small centre lobe. The Northern Marsh Orchid (Dactylorhiza purpurella) has rich reddish purple flowers, their lower lip is diamond shaped or triangular with darker markings, though some lips are broader and rounder. The leaves are broad and unspotted, slightly hooded at the tip. These two species dominate the Caithness orchid population and one needs to be thoroughly familiar with them in order to recognise other species when they are encountered. Both flower in late June and early July, the Heath Spotted appearing earlier in June. The Heath Spotted Orchid prefers an acid or neutral environment and is often encountered in heather moor or bog; the Northern Marsh, despite its name, prefers a sweeter grassy place, rarely being among heather.
Orchids superficially similar to the above two can be found. The Common Spotted Orchid (Dactylorhiza fuchsii) is picked out from the Heath Spotted by its obviously larger central lobe of the lower lip and its preference for only the most sweet grassy ground - it is scattered sparsely around the county. Dactylorhiza incarnata, the Early Marsh-Orchid has always had a distinct red-coloured flower when I have encountered it in Caithness, although white or pale-pink versions occur elsewhere. Its leaves are yellow-green and unspotted and it likes the sweet grassy places. Orchis mascula, the Early Purple 0rchid occurs, so far as I know, only on the east coast, notably in the valley of the Lybster burn between the road and the sea and it is to be seen during May before any other purple orchid is on show. Gymnadenia conopsea, the Fragrant Orchid is common in the sweeter places (Dunnet links near the forest is a good place to look). It has pink unmarked flowers and broad unmarked leaves. The perfume is strong and varies from a sickly-sweet to a very pleasant clove scent. A recent new discovery is a colony of Dactylorhiza majalis occidentalis, the Irish Broad-leaved Marsh Orchid which has the distinctive combination of broad leaves with large purple spots on them. The flowers are various purple colours usually because of hybridisation with our two common orchids.
Two green-flowered orchids are readily recognised. The Lesser Twayblade (Listera cordata) is found on heather moors and the two heart-shaped opposite leaves part way up the stem are immediately recognisable. The problem is to notice it at all since it grows among heather but is too short to rise above it. Its relative, the Twayblade (Listera ovata) is much bigger with a pair of elliptical leaves and likes a quite different habitat. It is restricted to calcareous seashore turf (Dunnet links again!) and rich calcareous marshes (Scrabster Loch area). The Frog Orchid (Coeloglossum viride) has the same small dark green flowers as the Twayblades, but the normal shapes of orchid leaves alternately arranged on the stem. It occurs sparsely, mainly by the sea, but it is rarely more than 3 inches high so easily overlooked. Two rather larger green-yellow flowered orchids are the elegant Butterfly Orchids. They are the lesser Butterfly (Platanthera bifolia) and the sturdier Greater Butterfly (Platanthera (chlorantha), both of which have a very distinctly butterfly-like flower. Both are pretty rare in the county.
Last, and almost least, is the Small White Orch!d (Pseudorchis albida), rare and scarcely flowering. This is probably because individual plants are short-lived but set seed which takes many years to germinate. It is a mere 4" high with small white flowers, which is sufficient to distinguish it from other local orchids. It occurs on poor exposed soil which is not too acid.
There is still much to learn about the distribution of our orchids, and I suspect at least one species remains to be discovered. So please help!