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Tripleurospermum maritimum [Sea Mayweed]: Another Example

Conical Cells
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#1 Andrea B.

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Posted 19 May 2015 - 19:52

Blum, A.G. (2015) Another Example of Tripleurospermum maritimum (L.) W.D.J. Koch (Asteraceae) Sea Mayweed. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...nother-example/

Shore Cottage, Southwest Harbor, Maine, USA
26 July 2014
Wildflower

Synonyms:
  • Matricaria maritimum L.
  • Scentless Chamomile
  • Sea Chamomile
Comment:
I have identified this specimen as being Tripleurospermum maritimum based on its slightly sprawling habit, coastal location and the fact that the leaves remain fleshy to the very tips. There is some disagreement about whether T. maritimum and its very close cousin T. inodorum should be separate species.
Rørslett (2012) first showed T. maritimum in ultraviolet(1). This example also also exhibits a UV-absorbing appearance under the BaaderU UV-pass filter.

Reference:
1. Rørslett, B. (2012) Tripleurospermum maritimum (L.) W.D. Koch (Asteraceae) Sea Mayweed. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...um-sea-mayweed/
2. New England Wild Flower Society (2015) Tripleurospermum maritimum (L.) W.D.J. Koch. Scentless Chamomile. https://gobotany.new...rmum/maritimum/


Equipment [Nikon D600-broadband + Carl Zeiss 60mm f/4.0 UV-Planar]

Visible Light [f/11 for 1/2.5" @ ISO-400 with onboard Flash and Baader UVIR-Block Filter]
This specimen is a bit battered and also hosts some critters.
Attached Image: tripleurospermumMaritimumVisFlash_072614shoreCottageSwhME_24188origpn.jpg

Visible Light [f/11 for 1/1.6" @ ISO-400 with onboard Flash and Baader UVIR-Block Filter]
The thread-like leaves remain fleshy until the tip.
Attached Image: tripleurospermumMaritimumLeafVisFlash_072614shoreCottageSwhME_24164origpn.jpg

Ultraviolet Light [f/11 for 2" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter]
The rays and disk are UV-absorbing. There is some iridescence on the top surface. Each ray has two slightly darker stripes.
Attached Image: tripleurospermumMaritimumUVBaadSB14_072614shoreCottageSwhME_24174pf.jpg

Ultraviolet Light [unresized crop from preceding foto]
Conical cells.
Attached Image: tripleurospermumMaritimumUVBaadSB14_072614shoreCottageSwhME_24174pfCrop.jpg

Visible Light [f/11 for 1" @ ISO-400 with onboard Flash and Baader UVIR-Block Filter]
An abaxial view of the rays and involucre.
Attached Image: tripleurospermumMaritimumAbaxialVisFlash_072614shoreCottageSwhME_24201pn.jpg

Ultraviolet Light [f/11 for 15" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter]
A long exposure was taken so that multiple flashes could be used.
The abaxial rays show quite a lot of iridescence.
Attached Image: tripleurospermumMaritimumAbaxialUVBaadSB14_072614shoreCottageSwhME_24210origpn.jpg
Andrea G. Blum
Often found hanging out with flowers & bees.

#2 nfoto

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Posted 19 May 2015 - 20:17

Your identification appears to be spot on.

The UV signature of your specimen also is almost identical to the European plants I have photographed in UV. That includes the two longitudinal stripes on the ligules.

#3 colinbm

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Posted 20 May 2015 - 01:41

Nice to see both sides Andrea
The UV dark parallel lines, on the petals, appear to be like folds or grooves, are they not causing the change in density of the light / shadows ?
Col

#4 Andrea B.

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Posted 20 May 2015 - 05:16

The grooves have something to do with it, but I'm not sure what exactly. It could be that because the grooved stripes are thinner, more of the underlying UV-absorbing pigments/chemicals can be seen. Or it could be that the grooved stripes are reflecting differently because the conical cells along the grooves are at a different angle than those on the flatter areas of the rays. Certainly some portions of some grooves appear folded enough to create a simple shadowed effect. But many of the grooves are well-lit and not folded in on themselves.
Andrea G. Blum
Often found hanging out with flowers & bees.