Columbia Hybrid Lady's Slippers in Eastern Washington

On May 20 I was out orchid hunting in eastern Washington.  After visiting two locations I visited a third location and found a mixed population of flowers some of which looked like the Mountain Lady's Slipper, Cypripedium montanum, other like the Northern Small Yellow Lady's Slipper, Cypripedium parviflorum var. makasin, and some that were obviously natural hybrids of the two, the Columbia Hybrid Lady's Slipper, Cypripedium x columbianum.  These all grow together and may all be hybrids.  The difference in the color of the pouches is the obvious clue.  The Yellow Lady's Slipper is named for its deep yellow pouch and the Mountain Lady's Slipper has a white pouch, but many flowers in this population have pouches that vary from pale yellow to cream.  Something in this population, probably the Yellow Lady's Slipper was very fragrant, too.

Small Northern Yellow Lady's Slipper look-alikes

Cypripedium parviflorum var. makasin

Mountain Lady's Slipper look alikes
Cypripedium montanum

Columbia Hybrid Lady's Slipper

Cypripedium x columbianum

Cypripedium x columbianum

Cypripedium x columbianum, the Columbia Hybrid Lady's Slipper, is a natural hybrid of Cypripedium parviflorum, the Yellow Lady's Slipper, and Cypripedium montanum, the Mountain Lady's Slipper.  When found it is often growing with one or both parents.  In an undisclosed location in Washington there is a population of well over one hundred plants that includes this hybrid.  In fact, I am putting all the plants found at this location under this name since it is doubtful that any of them are pure Cypripedium parviflorum or montanum, though some of the flowers look like one or the other parent.  The flowers that are clearly hybrids have neither the white lip of Cypripedium montanum, nor the yellow lip of Cypripedium parviflorum but range in the color of the lip from off white through ivory to pale yellow.

flowers that look like Cypripedium parviflorum

flowers that look like Cypripedium montanum

flowers that are clearly Cypripedium x columbianum

(intermediate between the two parents as evident especially in the color of the lip)