White Bog Orchid
(Platanthera dilatata)
There are lots of Orchid species. Some books say that there are over 35,000 species in the
Orchid family.
The orchid genus Platanthera has 33 different species.
The white bog orchid is a widespread species split into three varieties
based on spur length and shape.
In variety "albiflora", the spur is club-shaped and shorter than the lip.
In the variety "dilatata" the spur is more slender and equal in length to the lip.
The variety "leucostachys" has strongly curved spurs that are more than
1.5 times longer than the lip.
All of the varieties are similar in having numerous, small, white flowers
clustered into a thick, elongated spike borne at the tip of leafy tall stems.
The lip petal is distinctive in being
conspicuously broader at the base (“dilated”) than the smooth, tongue-shaped tip.
(see http://www.fs.fed.us/wildflowers/plant-of-the-week/platanthera_dilatata.shtml)
ID thanks to Lu