I got the x alaskanum from Planteck International or Planteck Biotechnologies in Quebec, they seem to use both names.
http://www.planteck.com//en/
Ursula, the x alaskanum has to be planted outside, it requires lots of cold, I was concerned that it might not be cold enough here, but if Kathy has success with guttatum at her location, mine should receive plenty of cold here.
Quoted from Planteck site.
"A natural hybrid between Cypripedium guttatum and C. yatabeanum. This most northern lady’s slipper has an attractive pitcher-shaped pouch, white with purple spotting, prized by collectors. This is an easy one to grow and spreads quickly but requires a longer cold period (minimum 5 months under 4 C or 39 F)."
