Anthriscus sylvestris [Cow-Parsley]

[nfoto]

Rørslett, B. 2013. Anthriscus sylvestris (L.)Hoffm. (Apiaceae). Cow-Parsley. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...is-cow-parsley/

 

Anthriscus sylvestris (L.)Hoffm.

NO: Hundekjeks

SE: Hundkäx

DK: Vild Kørvel

FI: Koiranputki

DE: Wilder Kerbel

EN: Cow-Parsley; Keck

 

This is a medium tall, to 1m, perennial umbelliferous species widely distributed in Eurasia. It may be the most common representative of the Apiaceae in Europe. Although not generally considered as a weed, its primary habitats are found in open landscapes often near settlements. It can occur in forest clearings and along brooks and rivers, though.

 

A. anthriscus develops massively on road verges and open meadows and flowering typically occurs mid to end of June. If you scrutinise such a stand up close, the inflorescences are teeming with pollinators, small and large One can wonder why A. sylvestris attracts such crowds of pollinators as the individual flower itself is small.

 

Image reference: Scanpix.no :sy71fcf7

 

Massive development of A. anthriscus in a rural landscape is an ubiquitous sight in the second half of June.

 

Plants for UV photography were collected on several occasions near Oslo, Norway June 2012 and 2013.

 

Image reference: ANTH_SYL_I1306223224_VIS.jpg

Visible light: Nikon D300, Medical-Nikkor 120 mm f/4 lens, built-in ring flash.

 

Image reference: ANTH_SYL_I1206130645_UV.jpg

Ultraviolet light: Panasonic GH-2, Coastal Optics 60 mm f/4 lens, Baader U2" (Venus) filter, SB-140 flash.

 

Ultraviolet light: Panasonic GH-2, Coastal Optics 60 mm f/4 lens, Baader U2" (Venus) filter, overcast daylight and strong wind. Video frame from HD video footage.

 

To paraphrase Bob Dylan, the "answer is blowing in the wind". The nectaria are disc-shaped and exhibit strong specular reflectivity. In UV this is seen as brilliant flashing against a darker background. The entire inflorescence becomes like a shimmering of stars when you see it in UV and there is ever so slight wind. Even in perfectly calm weather, the strong signalling would be present as long as the eye point moves about just like an approaching pollinators. It is food for thought that this glittering is not seen in visible light at all. Even though the nectaria are "wet" in appearance also seen in visible light, the tendency to show specular reflections is lower than in UV. Thus, even the ring flash used in the visible reference shot only produced mild reflections.

 

References:

http://www.ultraviol...ure-references/

 

[Published 23 June 2013]

[Andrea B.]

That is so very interesting - the flashing in the wind.

[nfoto]

I am about to process the UV stacks from yesterday so added details can be shown. Also, shall look into if a small video clip can be made and uploaded.

[nfoto]

Well, this is what an inflorescence of Anthriscus sylvestris look like up close on a breezy, overcast day in UV..The signalling effect from the UV-reflective nectaria should be clear enough even through the footage otherwise is pretty wind-blown. The inclement light conditions did not allow me to put the camera on a higher frame rate so the swaying in the breeze could be dampened by slow motion.

 

ANTH_SYL_UV_Video.avi

UV video clip: ANTH_SYL_UV_Video.avi

 

Panasonic GH-2, Coastal Optics 60 mm f/4 APO lens, Baader U2" (Venus) filter, daylight.

[Andrea B.]

This video is awesome !!! That is some kind of signaling for sure.

 

(We need to figure out how to have the movie play in the post. There must be a way. I had to download an app to play this AVI on my Mac.)

[nfoto]

Yes, there probably is a clever, more polished trick to this. However, filling up this site with video clips is not my idea. This was a one-off to understand better what is going on. I might clamp down on allowing further video unless we happen to find a better approach.