It is sometimes a surprise to people, even experienced growers of orchids what a convoluted process it is for an orchid to come into flower. While tropical orchid growers may recognise the twisting of the flower bud, it is usually forgotten that our native orchids do the same thing. The flower bud starts just like any other flower and then twists through 180 degrees before opening. This photograph of a Butterfly orchid taken from the side shows exactly this with the twist in the stem. These lovely flowers are pollinated by long-tongued moths that can reach down to the nectar at the end of the spur, which is clearly visible. Interestingly, these plants were common around Shrewsbury when Darwin was growing up and he probably witnessed the moths pollinating them, which allowed him to make the suggestion that it was a hawk moth with a long tongue which was the pollinator of Angraecum orchids from tropical Africa long before the moth was discovered. The similarity of structure between the butterfly orchid and the tropical moth pollinated orchids is striking.
![]() This picture of an Early Purple orchid is interesting because of the colour. This is one of the species that seems to have very little colour variation, like Butterfly orchids. On the other hand some species, most notably the Common Spotted has an enormous rage of shades from white through to deep magenta. In between these two you find species which have uncommon variation. One of these is the Pyramidal where in some sites they turn up in white. All this may seem like a simple observation, but there are implications for the curious mind. The Common Spotted gives the impression that colour is controlled by more than two genes. Snapdragons have a simple red/white system with pink in the middle, so there are broadly three shades, whereas Common spots have an almost continuous range between the two extremes. We would assume from that that there are at least three genes involved, maybe more. This sort of variation is simple compared with the colour and pattern variations that we find in Bee orchids. The Common Spotted throws up another form of variation which is interesting because it may well be heavily modified by the environment. This, as if you had not guessed, is leaf spotting. We are at this time involved in a project to determine the interactions which create these lovely leaf patterns and whether they remain the same every year.
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AuthorDr Wilson Wall, grower of orchids. A scientist by inclination and training. Categories |