Senecio jacobaea [Common Ragwort]: Another Example

[JMC]

Crowther, J.M. (2020) Another Example of Senecio jacobaea L. (Asteraceae) Common Ragwort. Flowers photographed in ultraviolet light and visible light. https://www.ultravio...-more-examples/

 

Synonyms:

• Jacobaea vulgaris
  

Other Common Names:

• Common Ragwort
  
• Ragwort
  
• Stinking Willie
  
• Tansy Ragwort
  
• Benweed
  

Comment:

Senecio Jacobaea a very common wild flower in the family Asteraceae that is native to northern Eurasia, usually in dry, open places, and has also been widely distributed as a weed elsewhere. Its poisonous qualities can make it a serious weed of paddocks and gardens backing onto fields grazed by horses or cattle. Ragwort is a tall erect plant to approximately 90cm (3ft) bearing large flat-topped clusters of yellow daisy-like flowers from July to October. It has finely divided leaves with a basal rosette of deeply-cut, toothed leaves. The plant is usually a biennial (living only two years and flowering in its second year) but damage to the base of the plant can make the plant behave like a perennial (living indefinitely), as new rosettes are formed. A very high nectar producer It was rated in the top 10 for most nectar production (nectar per unit cover per year) in a UKplants survey conducted by the AgriLand project which is supported by the UK Insect Pollinators Initiative.

 

In the UK, ragwort provides a home and food source to over 70 species of insect. 30 of these species of invertebrate use ragwort exclusively as their food source with another 22 species for which ragwort forms a significant part of their diet. English Nature has identified a further 117 species that use ragwort as a nectar source whilst travelling between feeding and breeding sites, or between metapopulations. These consist mainly of solitary bees, hoverflies, moths, and butterflies such as the small copper butterfly.

 

General information from RHS Gardening website and Wikipedia.

 

This was photographed in a garden environment in Surrey, UK, in July 2020.

 

References:

1. Wikipedia (acc 13 July 2020) Jacobaea vulgaris. Wikimedia Foundation, San Francisco, CA.

2. RHS Gardening (acc 13 July 2020) Senecio jacobaea. The Royal Horticulture Society, London, UK.

 

 

UV Light

Egham, Surrey, UK

July 2020

Wildflower, garden environment

 

Equipment [Nikon D810 ACS UV conversion + Rayfact UV 105mm lens]

 

Ultraviolet Light [f/16 for 0.5s @ISO 1000 in Sunlight using ACS in-camera filter]

 

 

 

 

Visible light

Egham, Surrey, UK

July 2020

Wildflower, garden environment

 

Equipment [samsung Galaxy s10 mini]

 

Visible Light [auto settings in phone]

 

[colinbm]

Beautiful colour & contrast Jonathan.

What is the ACS in camera filter Please ?

[JMC]

Thanks Colin. That, as they say, is the 6 million dollar question. They don't sell the filters separately, and they don't publish the specs. I've used it for a while now, and it seems similar to a Baader U in how it renders UV 'colours'. However I've not taken one out to measure the transmission.

[colinbm]

OK, thanks Jonathan.

[bvf]

Yes, nice - beautifully sharp. I've recently photographed Ragwort as well using a Focotar-2 - not too bad, but couldn't get the sharpness that you got.

[Cadmium]

Jonathan, Excellent UV photo. Made me want one of those cameras... almost. I went to their sight, but didn't see any prices.

[JMC]

Thanks Bernard. I took about 20 shots with slightly different exposures and f stop values and this was the best of them. The main issue was the slight breeze, and with the plant about 70cm tall, it was very prone to movement. It also helps that these have been reduced in resolution for sharing here.

 

Steve, cheers. No, they don't publish the prices on their site, which is another one of their quirks. I got this one for a job I was doing a few years back, and price was less of a concern then - I needed something quickly, and they were one of the few suppliers in the UK who were near enough that I could go and visit them before ordering.

[Andrea B.]

Thank you for this lovely contribution, Jonathan.

[JMC]

Then same flower and similar lighting to the images above (take about a week later than the initial photos) but taken using a Monochrome converted Nikon d850 with a 200mm f4 Micro Nikkor and StraightEdgeU Gen II filter.

 

Settings; ISO400, f22, 2/3s exposure time. Saved as jpeg in monechrome camera and then reduced in size in Photoshop. Slight tweaking of the curve, and small amount of cropping at the left and right sides.