Platanthera dilatata  (Tall White Bog Orchid)
William Weber calls this Limnorchis dilatata
Orchidaceae  (Orchid Family)

Montane. Wetlands. Summer.

Frederick Pursh named this plant Orchis dilatata in 1814, John Lindley named it Plantanthera dilatata in 1833, Per Axel Rydberg named it Limnorchis dilatata in 1901, and the plant has endured a number of other name changes.

"Platanthera", Greek for “wide anthers”, refers to the flower's broad anthers.  The Latin "dilatata", "broadened or expanded", refers to the dilated base of the lip of this orchid.