Sol,
No wulfenii has yellow blossoms, although pale ones. It bloomed for me once in MA. I almost cried though as it left one small increase!
Another possibility is that the various white flowers are from different mutations so that two different whites crossed give the complementary pink. That is w1 w1 W2 W2 (white) X W1 W1 w2 w2 (different white) gives W1w1 W2 w2 (pink). I had selfed Shampoo but didn't keep any of its kid to maturity. Too much like mom.
Kevin
