Andrea B. Posted July 9, 2013 Share Posted July 9, 2013 Blum, A.G. (2013) US Example of Erodium cicutarium(L.) L'Hér. ex Aiton (Geraniaceae) Redstem Filaree. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...ree-us-example/ Starbuck's, Route 35, Middletown, NJ, USA17 April 2013Wildflower Synonyms: Redstem Stork's BillComment:Chalwatzis (2013) first showed E. cicutarium in UV. This US example differs markedly in UV by exhibiting much more UV-reflectivity in its two lower petals and slightly more UV-absorption in its 3 upper petals. Its two lower petals also have a darker UV patch at their base. A bee would likely see the 2 reflective lower petals as their bee-UV-Blue while the 3 upper, slightly more UV-absorbing petals would appear to be more towards their bee-Blue. This is of course dependent on how much a bee's green receptor might be stimulated. It isn't particularly easy to tell whether this Magenta flower has any green peaks which push it more towards a Pink colouration. Redstem Filaree is a very tough little plant considered a noxious weed almost everywhere in the US. This not surprising given its explosively dihiscent method of flinging its parachuted seeds many feet from the mother plant whereupon the seeds' corkscrew awns screw themselves into the soil in response to moisture. The plant even grows well in the Mohave Desert where we saw large colonies during the Desert Wildflower Safari-2012. This specimen was found growing on a grassy strip between a parking lot and the highway. Reference:1. Natural Resources Conservation Service (2013) Erodium cicutarium Plant Profile. US Department of Agriculture. http://plants.usda.g...le?symbol=ERCI62. Chalwatzis, N. 2013. Erodium cicutarium (Geraniaceae). Redstem filaree. Flowers photographed in visible and ultraviolet light, including simulated bee colours. http://www.ultraviol...edstem-filaree/ Equipment [Nikon D600-broadband + Carl Zeiss 60mm f/4.0 UV-Planar] Visible Light [f/11 for 1/800" @ ISO 800 in Sunlight with Baader UVIR-Block Filter] Ultraviolet Light [f/11 for 1/8" @ ISO 1600 with SB-14 UV-modified Flash and Baader UV-Pass Filter] Ultraviolet Light [original of the preceding photo, desaturated and recropped]Here the original of the preceding photo was desaturted and recropped to illustrate the difference in UV-reflectivity between the upper and lower sets of petals. This is more evident in the upper right flower and the bottom left flower. The upper left flower has its lower petal set in shadow. Link to comment
Nico Posted July 9, 2013 Share Posted July 9, 2013 Very interesting! The flowers that you have captured show indeed a quite different and very interesting UV-signature. I'm surprised to see that within one species. It’s probably worthwhile to collect more UV-captures of that species from additional locations and see what the overall variation looks like!Best, Nico Link to comment
Andrea B. Posted July 9, 2013 Author Share Posted July 9, 2013 We may have some local variation here in New Jersey. Things like this do happen with UV signatures. I have another example or two in my files which I'll try to get to. And Bjørn has one from the Desert trip. As per the USDA Plants Database, in the US there are 3 subspecies of E. cicutarium. The one growing in New Jersey is Erodium cicutarium (L.) L'Hér. ex Aiton ssp. cicutarium. Link to comment
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