I got the info on Dietes from, "The World of Iridaceae" by Clive
Innes NOT "The World of Iris" published by the AIS. "Iridaceae" is
available and I can get you that info. You will be dissapointed by
the amount of stuff in the book on Dietes. (I'm not sure there is
even a photo.) Also it is a reference type book and my guess is that
it's expensive. Watch your snail mail for some stuff I sent along
with the return of you photo.