• Ultraviolet Photography

Senecio mohavensis [Mohave Ragwort]

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#1 Andrea B.

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Posted 22 February 2021 - 06:28

Blum, A.G. (2021) Senecio mohavensis A. Gray (Asteraceae) Mohave Ragwort. Flowers photographed in ultraviolet and visible light. https://www.ultravio...mohave-ragwort/

Death Valley National Park, California, USA
17 Feb 2017
Latitude: 36° 02' 05.2" N
Longitude: 116° 45' 24.2" W

Altitude: -69 meters BELOW sea level

So there you are in Death Valley. It's about 92°, there's strong winds, your are eyes full of dust and sweat, and the camera is misbehaving because black cameras tend to overheat in Death Valley. And then you find some Mohave Ragwort. You're in a national park where no picking is allowed so you can't take cuttings back to the air-conditioned hotel room to shoot at leisure. While this Senecio is not particularly rare, it's a plant which you will probably never see again. You decide what the heck and go for the in situ shots.
So, you know how that story ended. In a blur. Oh well. :rolleyes: I cropped in on the most in-focus parts. At least we can see that this Senecio has a UV-dark center and a few tiny UV-bright rays.

1. SEINet Arizona-New Mexico Chapter (acc 21 Feb 2021) Senecio mohavensis.
2. Jepson eFlora (acc 21 Feb 2021) Senecio mohavensis. Jepson Herbarium, U. of California-Berkeley, Berkeley, CA.

Nikon D750 + Micro-Nikkor 60/4.0 AFS
Attached Image: senecioMohavensis_vis_sun_20160217deathValleyNpCA_41423pnCropRes.jpg

Nikon D750 + Micro-Nikkor 60/4.0 AFS
Note purple stems. The leaves seemed almost succulent.
Attached Image: senecioMohavensis_vis_sun_20160217deathValleyNpCA_41425pnCropRes.jpg

Equipment [Nikon D610-broadband + Nikon 105mm f/4.5 UV-Nikkor]
Ultraviolet Light [f/8 for 1/30" @ ISO-400 with SB-14 UV-modified Flash and BaaderU UV-Pass Filter]
Attached Image: senecioMohavensis_uvBaader_sb14_20160217deathValleyNpCA_43364pnCropRes.jpg
Andrea G. Blum
Often found hanging out with flowers & bees.

#2 Andrea B.

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Posted 22 February 2021 - 21:09

I could be wrong about the temperature in the preceding comment. :rolleyes:

An interesting side-note to this Death Valley trip. While we were there it actually rained one evening. A slow gentle rain. It was very unusual as Death Valley only gets between 2-3" of rain per year. It always surprises me that anything grows at all.
Andrea G. Blum
Often found hanging out with flowers & bees.

#3 Bill De Jager


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Posted 23 February 2021 - 00:56

I hear your frustration, Andrea but your results were still useful and informative considering how shooting in wind can turn out.

Death Valley has a great deal of variability in its rainfall from one year to the next. While much of the North American desert region gets the majority of its precipitation during the summer months, the more westerly desert areas - the Mojave and Great Basin deserts - get most precipitation during the winter months. Therefore the following data are based on a July-June rainfall year, something that's normal in California but which may seem strange in most other places. Figures are for park headquarters at Furnace Creek on the floor of Death Valley, at nearly the driest and hottest location in the park. The elevation there is 58 meters below sea level (-190').

Average annual rainfall, 1990-1991 rainfall year through 2019-2020 rainfall year: 55mm (2.16")
Driest rainfall year (1993-1994): 6mm (0.24")
Wettest rainfall year (2004-2005): 163mm (6.44")



During one of my early visits to Death Valley, in March of 1978, enough rain had fallen that there was a salt lake in the lowest part of the valley. Where I was hiking in the Panamint Mountains there was a flowing stream where usually there was only deep groundwater.

I haven't been to Death Valley in maybe eight years now so I'm very eager to return there with (cameras for different spectral ranges!) once I'm vaccinated and the pandemic eases.

Edited by Bill De Jager, 23 February 2021 - 00:57.

#4 Andrea B.

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Posted 23 February 2021 - 01:07

I have loved both trips taken to Death Valley. It is completely fascinating with quite a wide range of features - more than most folks realize I think.
One of the most wonderful experiences on the last trip was seeing the desert Pupfish in D.V. and also east of the park in Nevada at the Ash Meadows Wildlife Refuge (highly recommended if you've never been). Amazing that those little fish are living in a desert.
Andrea G. Blum
Often found hanging out with flowers & bees.