A Welsh regional issue from issued in 1987 to mark the centenary of the publication of Flora Cambriensis. The four stamps depict species of wild orchids which only grow in Wales. The Dark Helleborine is only found growing on the coal tips of the valleys of South Wales, where is seems to have evolved to absorb and make use of the finest coal dust. The Bot-fly orchid belongs to Bee orchid family whose species’ flowers mimic specific insects both visually and in scent. The males of the insects are seduced into pseudo-copulation to pollinate the flowers. This species mimics the parasitic bot-fly whose larvae live in sheep nostrils. The Harlots Slipper orchid is named after the colour and shape of the flowers. More puritanical sects would dig up and burn these plants lest they inflame the passions of local men. The Satyr Orchid is also named after the appearance of the flowers. The bulbs were used to make an aphrodisiac tea, based on their  resemblance to testicles and the ‘perkiness’ of the satyr flowers.
The stamps were as usual available in sheets of 12