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Ranunculus acris [Common Buttercup]: More Examples

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#1 JMC

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Posted 02 September 2018 - 13:15

Crowther, J.M. (2018) More Examples of Ranunculus acris L. (Ranunculaceae) Common Buttercup. Flowers photographed in ultraviolet light. http://www.ultraviol...mmon-buttercup/

Write up details based on AG Blum's article: http://www.ultraviol...tall-buttercup/

Synonyms:
  • Ranunculus acer auct.
  • Ranunculus stevenii Beck
  • Meadow Buttercup
  • Tall Buttercup
  • Giant Buttercup
Comment:
R. acris is usually found in damp areas. It can be distinguished from the similar R. repens (http://www.ultraviol...ping-buttercup/) and R. septrionalis by its stalkless and deeply divided leaflets.4 These were photographed in a garden environment in Surrey, UK.

The shiny corolla of the various buttercups makes for a little difficulty when photographing them in either visible or UV light.4 This reflectivity comes from the arrangement of flat epidermal cells and air gaps giving the flower a glossy shine.3

In the UV Sonnar shot you can see the white 'blowout' that can occur in the photograph. We have speculated that this shininess may also act as a kind of pollination signal in various flowers?4 In these buttercups the dark UV bullseye matches the visible bulleyes which are darker yellow than the rest of the corolla.

The images also show a dark, highly UV absorbing, edge of the petals.

Reference:
1. Mittelhauser et al. (2010) Tall Buttercup, page 295. The Plants of Acadia National Park. The U. of Maine Press, Orono, ME.
2. Newcomb, L. (1977) Tall Buttercup, page 242. Newcomb's Wildflower Guide. Little, Brown & Co., New York City, NY.
3. Vignolini et al. (2011) Directional scattering from the glossy flower of Ranunculus: how the buttercup lights up your chin. Journal of the Royal Society Interface, v9 no71 pp1295-1301.
4. Blum, A. G. (2012) Ranunculus acris L. (Ranunculaceae) Tall Buttercup. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...ll-buttercup-1/


SET 1
Egham, Surrey, UK
May 2018
Wildflower, garden environment

Equipment [EOS 7D ACS UV conversion + Zeiss 105mm UV Sonnar + EOS/Hasselblad adapter + EOS 35mm Extension tube]

Ultraviolet Light [f/8 for 1.6s @ISO 400 in Sunlight using ACS in camera filter]

Attached Image: IMG_8394 2768k 1pt767 tint a small.jpg

Attached Image: IMG_8394 2768k 1pt767 tint a cropped small.jpg


SET 2
Egham, Surrey, UK
May 2018
Wildflower, garden environment

Equipment [EOS 7D ACS UV conversion + Rayfact 105mm f4.5 lens]

Ultraviolet Light [f/11 for 2.5s @ISO 400 in Sunlight using ACS in camera filter]

Attached Image: IMG_8362a.jpg
Jonathan M. Crowther

http://jmcscientificconsulting.com

#2 Andy Perrin

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Posted 02 September 2018 - 15:51

There is an error in the original info that you copied from here. The glow does not arise from conical cells because the buttercup doesn’t have them. Instead, its epidermal cells are flat with an air gap behind them and this is why you get the intense reflection. This is what it says in the original Vignolini paper.

In fact Vignolini draws a contrast between the buttercup with its flat cells and the yellow rose with conical cells (which does not exhibit the glossiness).

Edited by Andy Perrin, 02 September 2018 - 15:53.


#3 JMC

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Posted 02 September 2018 - 16:04

Updated the post Andy.
Jonathan M. Crowther

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#4 Andy Perrin

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Posted 02 September 2018 - 16:08

Thanks, we should ask Andrea to update the other post.

#5 Andrea B.

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Posted 03 September 2018 - 01:24

fixed!

Nice addition to the collection of UV floral signatures.
Andrea G. Blum
Often found hanging out with flowers & bees.