What we see in the second picture is UV induced visible fluorescence, using my Nichia 365nm UV LED lamp as exciter. No filter was used in that case, so what we see here is a mix of visual and some reflected UV light.
The flower center, as may be seen in the second shot, has a very strong UV reflectance, even if it appears dark brown/black in the visible shot. One may assume that this is intended together with the highly reflective UV pattern at the end of the flower petals, to attract pollinators like a "helicopter landing port".
[As usual, a click on an image opens up a larger one.]
Visual shot:
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UV induced fluorescence shot:
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So I hope you like it as much as I do....
Stay tuned, more will follow on that fascinating subject...
More info on this very interesting field may be found on my site http://www.pbase.com/kds315/uv_photos