Thanks for chiming in. I can say that having seen the real prints they are absolutely stunning. This one just shines. I never thought about it being a super long exposure, therefore the flower 'sagging' making it look like a multiple exposure. Good point!
Suzanne, he did do some figure studies using this technique as well, unfortunately the MIA didn't have any of those prints, however.
As an aside, the museum just received a large gift (400 prints) from a collector in North Dakota, some of which are going up on exhibit in July.
Check out http://www.artsmia.org if you live in the area. The exhibit is free.