This may have been best posted in 'Hybridizing How to's', but I started it here and may as well forge ahead.
I get asked fairly often why flowers on the same plant 'look different' and so I thought I'd get pictures of the bloom sequence while I still have an abundance of flowers. The water temps have dropped from the mid -90's to the low 80's and the show of flowers is noticeably tapering off.
Anyhow, here are the first, second and third day flowers on Dr. Pring's cultivar N. 'Director George T. Moore'.
The first day the stamen are upright and the nectar cup full of fluid and fully exposed to the pollinators. It is on the first day that the stigma are most receptive to pollen.
On the second, the stamen fold over and prevent access to the stigma. The business at hand on the second day is pollen production as fertilization of the ovaries should have been completed on the first day flower.
The third day, the flower is a mess!.. Most stamen have retracted and can offer viable pollen if it has not all been stripped by the bees, but the nectar cup, while exposed, is dry and no longer trying to attract bees.