In the tropics, they're outlandish: huge, exotic blooms ranging in colour from tangerine to puce, from snow-white to maroon, the world's most spectacular flowers.
In Britain, where the orchid season is about to begin, they are more restrained, usually elegant spikes in pastel shades, from pale lilac to purple, but here too there is an undeniable glamour and fascination about orchids.
We have about 50 wild orchid species in Britain, which is handy as that is a challenging but attainable number if you wanted to spot them all in a single summer. Fancy it? In practice, you won't quite see them all, because at least three of our species are too rare, headed by the legendary ghost orchid, which disappears for years at a time – it resurfaced on the Welsh borders in September 2009 for the first time since 1986.
The other two rarities – the lady's slipper and the red helleborine – are so scarce that they are continually guarded on a tiny handful of sites and public access to them is more or less impossible.
But the majority can be seen, as long as you're prepared to put in the time. Many of them, such as the greater butterfly orchid, are lovely – amongst the most beautiful of all our wild flowers. Others, such as the bee orchid or the fly orchid, are fascinating mimics of insects. But the question is: where do you start?
Orchids are often found in calcareous soils – soils with an underlying stratum of calcium carbonate, be it chalk or limestone. The Wildlife Trusts partnership has just produced a guide to orchid sites, listing 40 nature reserves where orchids can be found. You can access it at www.wildlifetrusts.org\orchidsites.
Here we give our own mini-catalogue of some of the more familiar orchid species and their sites, taken from the guide. We hope this is all you need to kick-start what might become your Orchid Summer.