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The Wild Orchids of Norfolk
The Wild Orchids of Norfolk
For our last indoor meeting of the 2017-18 season we welcomed Roger Jones from the Norfolk Wildlife Trust to tell us about The Wild Orchids of Norfolk.
Roger started by giving us a little information about the Norfolk Wildlife Trust. For example, it is the oldest wildlife trust in the country founded in 1926. It has 38 sites across Norfolk consisting of areas of between 435 and 1000 acres. It has 70 staff, 100 volunteers, 35,000 members and 300,000 visitors a year. The trust holds many events throughout the year including walks and talks. Roger had leaflets for anyone wishing to join.
The name orchid comes from the Greek ‘orkhis’, literally testicle, referring to the two tuberous roots characteristic of many species. The plants were thus associated with fertility, virility and sexuality. Orchids can be distinguished from other plants by shared novel evolutionary traits that are unique to the family. For example, the flowers have bilateral symmetry with the petals being highly modified. As the flower develops it turns up side down with the medial petal (labellum) becoming enlarged providing a suitable landing platform for pollinators, a process known as resupination. They have fused stamens and carpels and extremely small seeds. They are all perennial herbs, one of which is the familiar culinary vanilla. They are, of course, best known for the many exotic structural variations of their flowers.
The complex cross-pollination of orchids was investigated by Charles Darwin and published in his book, Fertilisation of Orchids in 1862. While a few orchids have self-fertilisation, most require a pollinator. Pollinators can be attracted by both colour and chemical means, but due to having highly specilised systems, pollination can be rare. As a result of this orchids remain receptive for a relatively long period requiring extended flowering, one reason why the cultivated varieties have become so popular. In extreme specialisation the labellum may attract a male insect by colour, shape and odour mimicking a receptive female. The male effects pollination while trying to mate with the flower. Some pollinators visit the flower only to gather volatile chemicals which they then synthesise into female attracting pheromones. One species of orchid traps the visiting insect. The only exit leads to the anthers that then deposit the pollen. A rare Australian species lives entirely underground, is never exposed to light and is pollenated entirely terrestrial insects. Some have asexual reproduction, propagating by producing offshoots.
The taxonomy of orchids is in constant flux as relationships are revised in the light of new genetic studies. An extinct bee fossilised in 15 – 20 million year-old amber was carrying pollen from of a previously unknown orchid. Other dating techniques suggest an origin of 100 million years making them contemporary with the dinosaurs. At that time all the continents formed a single landmass providing an explanation for their worldwide distribution. Bees appeared about 12 million years before orchids and collect far more of their requirements from other sources. This suggests that the orchid need the bees more than the bees need the orchid. In fact it seems that the orchids have been having to ‘keep up’ by developing new ways of attracting them. With many orchids being pollinator specific the loss of the insect will mean the loss of the orchid.
World wide there about 30,000 species of orchid occurring on every continent except Antarctica. As most species are indigenous the number found in Britain falls to 55 while Norfolk boasts only about 23. The only other family approaching the large number of species of orchids are the asteraceae - asters, dandelions and daisies, which unlike orchids can pollinate by wind or water and so need a much less specialised flower. Roger’s talk was accompanied by many beautiful slides showing the wide variation of forms that can be found even in Norfolk. It seems they can be found almost anywhere: woodland, roadsides, churchyards heath-land, coastal dunes, fens – yes anywhere. I think, as usual, the trick in finding them is to get your eye in. A friend of ours, just down the road, has them in his garden. He builds little fences around them for protection. Some of the problems of finding orchids are there comparative rarity: some are known to occur in just one small area, some as just one plant. It goes without saying that if you find one, on no account should you pick it.
The competition results for March:
1 Sue Thomas.
2 Audrey Harrod.
3 Sue Cunningham.
1 Sue Thomas.
Only one entry.
1 Prue Szczepanowski.
2 Dane Dalton.
3 Chris Dalton.
Our first outdoor meeting will be on Wednesday 16th of May, the THIRD Wednesday of the month. We will be visiting the Fairhaven Woodland and Water Gardens. We leave the village green at 12:00.