Neal, we just use paper coin envelopes. At least they worked properly when I sent pollen to Chuck Chapman in Canada.
White may be recessive to yellow, but not to blue. I have not read about it in World of Irises, I just found what happens. I asked Dave Niswonger who worked with TB amoenas & he agreed that keeping the white can be a difficult problem. But you never know what is behind the cultivars until you try. I used Paul black's 'Forte' to make a smooth red & out popped Reddy Set & 2 variegatas. I would not have expected it.
