Here are 4 wild Orchids to look out for in May. Orchid flowers are complex and have unique flowering parts and an amazing method of pollination. Orchid flowers have 6 tepals in two whorls. The 3 outer tepals enclose the flower. There are 2 inner tepals that enclose the reproductive parts and one, called the labellum, which is enlarged and may be prolonged backwards into a spur. The labellum forms the landing pad for pollinating insects. The reproductive parts consist of the pollinia, rostellum and stigmas arranged in a vertical structure called the column. In orchids pollen grains are fused together into a long club-shaped structure called a pollinium (plural pollinia) and transported whole by the pollinator.
Here are the flowering periods for the four orchids described.
|Early Purple Orchid
|Common Spotted Orchid
|Early Marsh Orchhid
The Common Spotted Orchid Dactylorhiza fuchsii is the most common orchid in Britain. It is found on grasslands and in woods. It is relatively tall, up to 50cm. It flowers from mid May to early August. and grows from a root tuber. Identified by its spotted leaves, it has a slight scent but, like all species in the Dactylorhiza genus, produces no nectar in its spur. It is pollinated by bees and flies. It has 2 pollinia which stick to the head of the pollinator as it attempts to access the spur. By the time the insect reaches the next flower the pollinia stick out horizontally and touch the sticky stigmas located below the rostellum on the upper side of the entrance to the spur.
The Early Purple Orchid Orchis mascula flowers from April to June.These photographs were taken in woodland in April. The orchid is short, 15 to 40 and the leaves are spotted. The labellum has an extension at the back into a long spur (shown in the centre below) which does not provide nectar. The labellum is 3-lobed. One ‘sepal’ and 2 ‘petals’ form a hood (bottom right) over the column which has 2 pollinia and 2 stigmas. The pollinating bee lands on the labellum and inserts its proboscis into the spur. As it does so one or both of the brown pollinia shown sticks to its head. As the bee flies to the next flower the pollinia swing forward through 90 degrees so that when the bee lands on the next flower the pollinia strike the sticky stigmas located below the rostellum on the upper side of the throat of the spur. The spur provides no nectar so this is an example of food deception which puzzled Darwin.
The Green-winged Orchid Anacamptis morio is found throughout Britain in meadows and pastures. It is short, usually less that 20 cm in height. It grows from a tuber and flowers in May and June. It has a purple labellum and a purple helmet with green veins. It has a spur which does not contain nectar and so practices food deception. It has a scent which attracts social and solitary bees. One theory is that food deception may result in fewer visits by pollinators but increase the chance of pollen arriving from another plant and hence reduce inbreeding.
The Early Marsh Orchid Dactylorhiza incarnata flowers from late May to late June in damp grassland and marshes throughout Britain. It is up to 40cm in height. It has no scent and produces no nectar but deceives inexperienced pollinators such as bumblebees, possibly because it is found in remote marshy areas where there are few rewarding flowers for pollinators. It grows from a root tuber and occurs widely across Eurasia as far as Siberia.