Finding an orchid is always a bit of a thrill! They are set apart from other flowers, they have that certain something extra. People will go miles to see a rare orchid just as others will go miles to see a rare bird.
One of the largest and most striking orchids you will find in Dorset is this one, the greater butterfly orchid (Platanthera chlorantha). Orchids are often named after something they resemble (bee, spider, frog, wasp, etc) but I find it hard to see any resemblance with a butterfly here. That said, it is a lovely flower. It has a spike of creamy white flowers that have a feint vanilla scent.
Not common, the greater butterfly orchid can be found in woodlands and grassland where the soil is calcareous so north Dorset is probably the most likely area, particularly Fontmell Down where they are numerous in June. They may not be common but, if you find one, you will probably find several. There is a lesser butterfly orchid which is much the same size but the individual flowers are apparently narrower and it has a stronger scent. I am not sure that the lesser grows in Dorset but I may be wrong. I would be happy if someone could enlighten me if it does!