Thanks, Kent.
[It's not that one. The reproductive units on my plant are tiny, and very close-set to the top center of the inflorescence.]
When I look at a (fairly well-aged) bloom on my plant I see distinctly separate, rather lax and tending to fold over each other, petals (sepals?); one of which sports a much darker purple-blue face.
I may pull blooms off today and bring them into better light to photograph.
