Apache beggarticks - Bidens ferulifolia in deep reflected ultraviolet photography making plant deterioration visible - plant forensics

Today some details caught my attention on the petals of a well known spring flower I have written about before, Apache beggarticks - Bidens ferulifolia shot in reflected ultraviolet photography using my "work horse" UV filter, the Baader-U filter, my XBV filters for simulating butterfly and bee vision as well as my Jupiter-U and Saturn-U deeper reaching UV filters. Lens was a CERCO 94mm quartz fluorite lens. Light source was a Xenon flash. All shots were done at about f8.

It is about the fading UV bullseye pattern when a flower ages, which gets not only visible when using the bee and butterfly vision simulating filters but also when using deeper reaching UV transmitting filters, which btw. are:
- Baader-U filter (approx. 320-395nm, effective peak approx. 375nm)
- Jupiter-U filter (approx. 280-385nm, effective peak approx. 365nm)
- Saturn-U filter (approx. 300-350nm, effective peak approx. 325nm)

What gets visible, is that the naked human eye does not see anything in the visible image except some lighter colored petals, but already the Baader-U filtered image starts to reveal some fading of the UV bullsyeye pattern (also called UV nectar guide) in the bottom flower compared to the two fresher flowers above, which gets more prominently visible when using the Saturn-U filter and surprisingly best when using the Jupiter-U filter. I have noticed earlier in outdoor shots, that reflected UV imaging reveals plant and specifically flower detoriation much earlier than visible light image does. But let's have a look at the following "plant forensic" images....

[click on image to see a larger one]

Visible light image (400 - 700nm):
 

Simulated butterfly vision (UV - VIS) using XBV3 filter:
 

Simulated bee vision (UV - VIS) using XBV6 filter:
 

UV image using Baader-U filter (approx. 320-395nm, effective peak approx. 375nm):
 

UV image using Jupiter-U filter (approx. 280-385nm, effective peak approx. 365nm):
 

UV image using Saturn-U filter (approx. 300-350nm, effective peak approx. 325nm):
 

Quadriptych of the above with sim. animal vision:
 

Quadriptych of the above with deep UV:
 

Quadriptych of the above with sim. animal vision in detail:
 

Quadriptych of the above with deep UV in detail:
 

Bidens has a prominent UV pattern, its petal tips are UV bright around 365nm, its center is quite UV dark. Here now it gets visible how this UV pattern fades away (lighter petails shifting towards 370nm reflection and quite ligter center i.e. much less contrasting overall appearance) when the flower ages (bottom flower) and this gets nicely visible here.

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