Columnist
Blooming marvellous Orchids seem unique in how they inspire such a devoted following, but why are there so many species of these much-loved plants, wonders Penny Sarchet
THE announcement of a newly recognised orchid species in Japan prompted discussion among our UK news team recently. Spiranthes hachijoensis is undoubtedly beautiful, and it is always surprising to hear of new species in well-studied countries. But I couldn’t help being slightly cynical about this one, which is very similar to another known species, but not as hairy.
My cynicism has its roots in the great divide between lumpers and splitters: the tendency among taxonomists and natural historians to prefer either to classify similar organisms as a single species or to split them up into multiple distinct ones. There are good arguments in favour of each approach, but the orchid family, which may be the largest plant family in the world, provides ample opportunity for splitting to run wild. For example, depending on your philosophy, there could be as many as 529 species of orchid in Europe – or only 102.
Nevertheless, Orchidaceae is an extraordinary family and may account for a tenth of all seed-producing plants. It boasts a staggering number of species, at around 25,000, and includes some of the most beautiful, startling and cunning flowers in existence. One member of this family is Vanilla planifolia, the source of vanilla, one of the world’s favourite flavourings.
The huge number of orchid species isn’t just the work of splitters, it also reflects an incredible range of different forms. This can feel surprising – we tend to think of orchids as delicate and rare, but they are also diverse and widespread. Why is this the case?
One person to ask this question was orchidologist Calaway Dodson, who, in 2003, tackled the issue of why there are so many orchid species in Ecuador in particular. He noted that Ecuador is the smallest country in the Andes, but that more than 3700 species of orchid had been recorded there, and proposed a number of features of orchids that may contribute to their ability to rapidly diversify into new species. Seeds were one of these: orchids produce a very large number of tiny, wind-disseminated seeds, providing plenty of scope to spread large distances
