Ultraviolet Flowers: Ranunculus ficaria

Ranunculus ficaria L.

Ranunculaceae

Ranunculus ficaria. Visible light

Visible light
Nikon D1H , UV-Nikkor 105 mm f/4.5, no flash

Ranunculus ficaria. UV light

UV light
Nikon D1H , UV-Nikkor 105 mm f/4.5 @800 ISO, FF filter + CC20C, SB-140

Ranunculus ficaria. IR light

IR light
Nikon D1H , UV-Nikkor 105 mm f/4.5 @800 ISO, Wratten 89 B, SB-140 + Wratten 87

Lesser Celandine has bright yellow flowers showing a very strong UV pattern. The petals have oily glands towards their base and this area absorbs UV. However, the UV-absorbing segment extends beyond this towards the tips of the petals..

The reflectance in near-IR is much less than in UV, but interestingly even here a two-zoned pattern can be demonstrated. This is the first example of such a trait found in my studies and I'm not certain about its ecological significance.