Washington has five species of Platanthera that weere formerly classified as Piperia, and this is the smallest of the five, not taller than 30 cm and with 2 cm flowers (including the long spur). It is known as the Flat-spurred Piperia, not for the shape of the spur but because it is parallel to the flower stem. It is supposed to be fragrant at night but I have never tested that. When it blooms the leaves have usually withered away and so all one sees is the bare flower spike with its blooms. It likes drier areas in full or part sun.
(Columbia River Gorge)