I also wanted to try breeding Mexipedium with Phrags. I was thinking "miniature" Phrags, and perhaps using Mexipedium as a stepping stone to create white Phrags.
I have been succesfull in actually getting seedpods and even germinating the seedlings in the lab! I was able to cross Mexipedium to Phrag. besseae, Phrag. longifolium, and Phrag. fischeri. Unfortunately I think we are dealing with a too far out cross. The seedlings grew for about a year in the lab, although I have to say they did not grow well, they seemed to keep proliferating, without making individual seedlings. After about a year they would crash and die on me.
I do know that earlier we had crossed Phrag. wallisii (warscewiczianum) to Mexipedium, and that actually made it out of the lab, but it was a weak grower, and never made it to blooming size. I think it too perished.
I have also tried crossing Mexipedium to Cypripediums and Paph's, but those never created viable seedlings. This probably tells you that Mexipedium is more closely related to Phragmipediums, but to me the fact that you get no blooming size hybrids between Phragmipedium and Mexipedium, and also because the flowers and the growth habit is so different warrants it to be a separate genus.
Robert
