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Erigeron tracyii [Running Fleabane]

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#1 Andrea B.

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Posted 10 June 2021 - 23:07

Blum, A.G. (2021) Erigeron tracyii Greene (Asteraceae) Running Fleabane. Flowers photographed in ultraviolet and visible light. https://www.ultravio...nning-fleabane/

La Secuela, Santa Fe, New Mexico, USA
10,13,25 May 2020
Wildflower

Synonyms:
  • Erigeron colomexicanus A. Nels.
  • Erigeron commixtus
  • Erigeron divergens var. cinereus A. Gray
Other Common Names:
  • Running Daisy
  • Tracy's Fleabane
.
Comment:
This Erigeron has rose striping on the outer portion of its abaxial rays. Both the buds and the spent flowers show a lot of this rose color. In full bloom most of the flower faces are white, but a few occasionally have a pinkish tint.

One primary difference between E. tracyii and its very close cousin E. flagellaris is the lack of plantlets on the ends of E. tracyii's long stolons. (See the 4th photo below.) Also the hairs of E. tracyii are not appressed like those of E. flagellaris. (See the stem in the 7th photo below.)

When these photos were made mid-May 2020, I had about a quarter-acre of this cheery Fleabane growing in front of the house. This year I had almost none because, I think, we did not get enough winter snow and early spring rain.

In Ultraviolet light, the rays are a dark false blue (front and back) and the center disc is UV-absorbing (black). There is a bit of brighter striping at the base of the rays.

References:
1. SEINet Arizona-New Mexico Chapter (acc 22 Mar 2021) Erigeron tracyii.
This is a southwestern biodiversity organization making use of the Symbiota portal software.
2. Southwest Colorado Wildflowers (acc 22 Mar 2021) Erigeron tracyii.
Website published and maintained by Al Schneider and hosted by Rocky Mountain Biological Laboratory.
3. Allred, Kelly W., Jercinovic, Eugene M., Ivey, Robert DeWitt (2021) Flora Neomexicana III: An Illustrated Identification Manual, Second Edition, Part 2, Erigeron Key, page 133. Print on demand at lulu.com.


Equipment [Nikon D610-broadband + Nikon 105mm f/4.5 UV-Nikkor]
unless otherwise noted

Visible Light [f/14 for 1/1000" @ ISO-1100 in Sunlight with Nikon D850 + Nikkor 70-200/4G AFS VR]
Note the amount of rose color on the unopened buds and the spent flowers.
Attached Image: erigeronTracyii_vis_sun_20200513laSecuela_6620pn01.jpg


Visible Light [f/11 for 1/400" @ ISO-220 in Sunlight with Nikon D850 + Nikkor 70-200/4G AFS VR]
On the left is a beautiful Juniper Hairstreak butterfly visiting a Fleabane flower.
When the light catches that green, it is beautifully iridescent.
Attached Image: erigeronTracyii_vis_sun_20200510laSecuela_6347pn01.jpg


Visible Light [f/11 for 1/400" @ ISO-200 in Sunlight with Nikon D850 + Nikkor 70-200/4G AFS VR]
The fully open flowers in this Fleabane patch are all white.
Attached Image: erigeronTracyii_vis_sun_20200510laSecuela_6337pn01.jpg


Visible Light [f/14 for 1/1000" @ ISO-640 in Sunlight with Nikon D850 + Nikkor 70-200/4G AFS VR]
Stolons are usually along the ground, of course. But this plant grew up between the rocks so the stolons had not yet found the dirt when I made this photo. There are no little plantlets at the ends of these stolons.
Attached Image: erigeronTracyii_vis_sun_20200513laSecuela_6629pn01.jpg


Visible Light [f/16 for 1/1.6" @ ISO-200 with Onboard Flash and Baader UV/IR-Cut Filter]
The disk flowers are in different opening stages on these three flowers.
Attached Image: erigeronTracyii_vis_flash_20200525laSecuela_20200nx2Crop.jpg


Ultraviolet Light [f/16 for 25" @ ISO-200 with Modified SB-14 and Baader UV-Pass Filter]
Three flashes were made in the 25" interval.
The pollen is more UV-bright than the disk flowers.
Look for the striping at the base of the rays along their edges.
Attached Image: erigeronTracyii_uvBaad_sb14_20200525laSecuela_20204pn01.jpg


Ultraviolet Light [f/16 for 25" @ ISO-200 with Modified SB-14 and Baader UV-Pass Filter]
Note that the stem hairs stick out and are not pressed close to the stem.
Attached Image: erigeronTracyiiAbaxial_uvBaad_sb14_20200525laSecuela_20269pn01.jpg


Visible Light [f/16 for 1/3" @ ISO-200 with Onboard Flash and Baader UV/IR-Cut]
The feathery involucre hairs make a pretty pattern around the base of the flower.
Attached Image: erigeronTracyiiAbaxial_vis_flash_20200525laSecuela_20220pn01.jpg


Ultraviolet Light [f/16 for 30" @ ISO-200 with Modified SB-14 and Baader UV-Pass Filter]
The "feather" details are even clearer in UV light.
The abaxial rose stripes are gone in Ultraviolet light.
Attached Image: erigeronTracyiiAbaxial_uvBaad_sb14_20200525laSecuela_20232pn01.jpg
Andrea G. Blum
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#2 Cadmium

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Posted 10 June 2021 - 23:15

Very nice! I like the three flowers together especially. :smile:

#3 colinbm

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Posted 11 June 2021 - 01:25

Nice collection Andrea
Unusual to see the back side of flowers.

#4 nfoto

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Posted 11 June 2021 - 09:26

Sometimes the front and rear views are strikingly different seen in UV, although being visually similar. Thus it is in general a good idea to record both views.

#5 Andrea B.

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Posted 11 June 2021 - 18:20

Thanks all.

Yes, Birna and I early on "discovered" that the abaxial (back or underneath) side
of rayed flowers can often hold either a visual or UV surprise. :bee: :bee: :bee: :bee:



I'm still intrigued by the "feathers" on the back side of this Fleabane. Those are just hairs on the underlying sepals, but the overall impression, especially in the UV photo, is of feathers. Way cool!



Fleabanes are the bane of my botanical existence when it comes to identification.
The pretty little daisy-like things look all the same.
Andrea G. Blum
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#6 nfoto

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Posted 11 June 2021 - 18:57

There are genera faring much worse than Erigeron when it comes to identification of species ....

#7 Stefano

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Posted 11 June 2021 - 19:05

There are a lot of dandelion-like flowers, when I find one I am never 100% sure it is an actual Taraxacum officinale.

#8 nfoto

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Posted 11 June 2021 - 19:39

Identifiying something as a genuine Taraxacum is a breeze. Basal rosette witrh coarsely toothed leaf margins; unbranched leafless and hollow stems with white latex sap oozing out, and dense composite flower heads with usually bright yellow flowers. The individual flower is always a ray flower, never disk flowers.

However, this genus is largely apomictic, meaning the traditional species concept is moot. Hence you can find the number of "species" ranging fron 1-10 to many thousands -- it all depends on the source you consult.

#9 Andrea B.

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Posted 11 June 2021 - 20:22

I think for those Euro Taraxacum not even DNA helps?? Just a slow fade between one plant and another. No place to "draw the line" and declare a species. :cool:
Andrea G. Blum
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#10 nfoto

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Posted 11 June 2021 - 21:43

We are veering off the thread here. It should be split and relevant part(s) moved elsewhere.

The Dandelion genus does not comprise 'Linnaean' species and unfortunately, will not fit into the rigid formal structure of taxonomy and botanical nomenclature.