The dorsal and lateral sepals of this orchid arch and converge to form a sort of hood above the column and lip. Viewed from above, it looks like the flowers are in bud but not opened. But if you put your face down by the ground and look up at the inflorescence, you can see into the open flowers! There is another greenish orchid with long bracts in the inflorescence: Platanthera flava. Care must be exercised when identifying either species; the morphology of the lip is perhaps the best field feature.
Scott Namestnik and I had the good fortune of seeing this plant in a state of FGB (full, glorious bloom) yesterday in a forest of hills and ravines near the Salamonie River. It is a challenge to find Coeloglossum in Indiana, and we owe a special debt of gratitude to Pete Grube, Jerry Sweeten, and Dave Hicks for helping us find it. The excellent discovery of this population was made by Tim Kimmel.
Remarkably, while I was attempting to get photos, Scott went exploring and found a small, sterile plant that could be a seedling of this orchid. Amazing! Of course, it could be something else, possibly a Liparis.
One of the best experiences for a botanist or a student of the flora is to visit a new site and learn lots of new species This is what happened on Sunday, and it was profoundly enjoyable!