Dear members, Has anyone done an investigation into why some flowers develop windows in their petals? I came to that question this morning when I noticed a late bloom on my Cypella herbertii (yes, they do have an exceedingly long season, but we've been having unseasonably warm and wet weather lately here on the S.F. Peninsula). I noticed that the portion of the outer tepals which form the cup are transparent. In most photos this portion looks white, but it is actually hyaline (or at any rate, it was on this morning's blossom). There are other plants noted for transparent windows in their petals. Are there any theories about how these might have evolved? David E.