Another two-cents worth.
There was an interesting comment made during this discussion that I didn't comment on, but just now saw it mentioned again. Somebody mentioned that I. pallida can have PBF. I just wanted to comment that I have never personally - ever - seen any purple on the foliage nor on the spathes or bracts of any selection of Iris pallida of any variety. Not even on cultivars that many doubt are pure I. pallida (but that have all the characteristics of the species).
On the other hand, I have seen PBF on lots of hybrids that have I. pallida as one parent, with the PBF apparently always coming from the other parent. Lots (if not most) hybrids that have I. variegata as the other parent (or even children of these removed by a generation of two) will show PBF, and some of these do resemble I. pallida somewhat.
Also, I realize the fact that when talking about unreduced gametes, I ignored the vegetative abnormalities that can result in polyploidy (still unreduced cells - but not gametes, and through various other happenstances. I didn't mean to imply that I think these unimportant, indeed as stated here, they are often the way that polyploids come to be.
best wishes to all,
Dave Fergusoncentral NM (where I haven't seen an Iris flower for several days now, and envy those of you who are still getting to enjoy them).
