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Erigeron philadelphicus [Philadelphia Fleabane]

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#1 Andrea B.

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Posted 08 July 2016 - 01:20

Blum, A.G. (2016) Erigeron philadelphicus L. (Asteraceae) Philadelphia Fleabane. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...ommon-fleabane/

Scherman Hoffman Wildlife Sanctuary, Bernardsville, NJ, USA
07, 10 May 2010
Wildflower

Synonyms:
  • Common Fleabane
  • Erigeron philadelphicus var. glaber Henry
  • Erigeron philadelphicus var. scaturicola (Fern.) Fern.
  • Erigeron purpureus Ait.
Comment: The feathery rays and pink tint are key features of the lovely Erigeron philadelphicus, native to North America. The specimen initially found within the Scherman Hoffman park could not be picked. So while the visible photographs of that plant are quite acceptable, the UV attempt failed due to the windy day. As I was leaving I found another somewhat battered specimen growing on the roadside just outside the park. Given that it would soon be mowed down, I picked one flower to take home for an indoor UV photography session. Like its cousins E. annuus and E. strigosus, the Philadelphia Fleabane has a UV dark central disk and UV-absorbing rays. The pollen is UV bright and also fluorescent under UV light.

Reference:
1. New England Wild Flower Society (2016) Erigeron philadelphicus. Philadelphia Fleabane. https://gobotany.new...philadelphicus/

UV Gear [Nikon D200-broadband + Rodenstock 60/4.5 UV-Rodagon]

Visible Light [f/8 for 1/500" @ ISO-500 in Sunlight with Baader UVIR-Block Filter]
Attached Image: erigeronPhiladelphicus_visSun_20100507schermanHoffmanNJ_7463pn.jpg

Visible Light [f/8 for 1/2000" @ ISO-400 with Nikon D3S + 60/2.8D Micro-Nikkor in Sunlight]
Attached Image: erigeronPhiladelphicusLeaf_visSun_20100507schermanHoffmanNJ_7476pn.jpg

Visible Light [f/8 for 1/1250" @ ISO-400 with Nikon D3S + 60/2.8D Micro-Nikkor in Sunlight]
Not all flowers show the same degree of pink tint.
Attached Image: erigeronVis050710schermannHoffmanNJ_41965origpn.jpg

Ultraviolet Light [f/8 for 1/1.5" @ ISO-500 in Sunlight with BaaderU UV-Pass Filter]
Strong breezes and a light leak through the aperture window prevented this from being a prime example of the UV-signature for E. philadelphicus. See below for additional examples.
Attached Image: erigeronUV050710schermannHoffmanNJ_41968origpn.jpg

Visible Light [f/8 for 1/30" @ ISO-500 with Onboard Flash and Baader UVIR-Block Filter]
Attached Image: erigeronPhiladelphicus_visFlash_20100514schermanHoffmanNJ_42543pn.jpg

Ultraviolet Light [f/8 for 1/2" @ ISO-500 with Nichia 365nm UV-LED and BaaderU UV-Pass Filter]
In the following two examples, the UV-bright pollen obscures the UV-dark disk florets that were seen above.
Attached Image: erigeronPhiladelphicus_uvBaad365Led_20100514schermanHoffmanNJ_42551pn.jpg

Ultraviolet Light [f/8 for 1/2" @ ISO-500 with Nichia 385nm UV-LED and BaaderU UV-Pass Filter]
Attached Image: erigeronPhiladelphicus_uvBaad385Led_20100514schermanHoffmanNJ_42554pn.jpg

UV-Induced Visible Fluorescence [f/8 for 2" @ ISO-500. Nichia 365 UV-Led (unfiltered). Lens with Baader UVIR-Block Filter. Photographed in Darkness.]
This photo was not formally colour-calibrated, so the colours of the Fluorescence may not be entirely accurate. The pollen is strongly fluorescent under an unfiltered Nichia 365nm UV-LED.
Attached Image: erigeronPhiladelphicus_uvBaad365Led_IndVisFluor_20100514schermanHoffmanNJ_42548rgbRend.jpg
Andrea G. Blum
Often found hanging out with flowers & bees.

#2 Andy Perrin

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Posted 08 July 2016 - 04:52

It may be UV-dark, but it's lovely nonetheless. I made some photos of fleabane (unsure of precise species) awhile ago, but yours are much nicer.

NEX-7, sunshine, Noflexar, 330WB80 filter, F16 20" ISO-200, denoised, sharpened, and white balanced to remove the blue cast, so not quite the Teflon white balance (but close).
Attached Image: fleabane daisy 1 sunshine 330WB80 Noflexar F16 20%22 iso200 denoise sharp remove blue cast small.jpg

Edited by Andy Perrin, 08 July 2016 - 04:54.


#3 Andrea B.

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Posted 08 July 2016 - 22:58

That looks good, Andy.

Look at the stem of the flower. If the hairs are short, tightly pressed, upright against the stem, then likely you have an Erigeron strigosus. If the hairs spread out from the stem almost perpendicularly, then you probably have an E. annuus. Both are common in your area. I can't quite tell about the leaves from this photo, but E. strigosus has leaves which are more linear, elongated. E. annuus has leaves which are broader in the middle.

If I'm reading the cues correctly, this is an E. strigosus = Rough Fleabane.
Andrea G. Blum
Often found hanging out with flowers & bees.