Epipactis gigantea is rightly named the Stream Orchid or Chatterbox. In the one place we've found it here in Washington, we found it growing in one large clump right beside the lake, so close, in fact, that it was difficult to get pictures without getting wet feet.
It was also very windy that day and we discovered why this orchid is known as the Chatterbox. It has a movable lip, not unlike a little mouth, that in the wind made photography very difficult. The story of our finding this native orchid is at: http://ronaldhanko-orchidhunter.blogspot.com/search/label/epipactis%20gigantea
The plant can be as tall as 100 cm, but the plants we found were only a little over 30 cm tall. The leaves are pleated and the flowers are around 3 cm in size, very beautiful and very showy. There can be up to twenty-five flowers per spike, though the most we've seen is ten.
The plant ranges from British Columbia south to Mexico and east to Montana, South Dakota and New Mexico. It is very rare in our area, but can be relatively common in some places. It is usually found in very wet areas and flowers during July and August.