nfoto Posted June 22, 2013 Share Posted June 22, 2013 Rørslett, B. 2013. Lathyrus pratensis L. (Fabaceae). Meadow Vetchling. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...adow-vetchling/ Lathyrus pratensis L.NO: Gulskolm: gulflatbelgSE: GulvialDK: Gul FladbælgFI: Niittynätkelmä IS: FuglaerturDE: Wiesen-Platterbse EN: Meadow Vetchling A perennial prostrate or climbing plant native to Eurasia, L. pratensis is found on open habitats such as shore or inland meadows, road verges, or along forest edges. It is usually common and abundant within its distribution area. Flowering commences in June and can continue throughout the summer. Each flower is small, bright yellow, and borne in lateral inflorescences scattered along the lax stems. Specimens collected and photographed near Oslo, Norway 22 June 2013. Image reference: LATH_PRA_I1306223219_VIS.jpgVisible light: Nikon D300, Medical-Nikkor 120 mm f/4 lens, built-in flash. This plant was collected in a rainy period and its flowers had started to wilt. Image reference: LATH_PRA_I13062240859_UV.jpgUltraviolet light: Nikon D600 broad-spectrum, UV-Nikkor 105 mm f/4.5 lens, Baader U2" (Venus) filter, Broncolor studio flashes (uncoated Xenon tube). Detail from a stack comprising 27 frames in Zerene Stacker. In UV, L. pratensis has a quite UV-reflective corolla with UV dark wings. The sail (upper part of corolla) has a crenelate or ridged pattern of large cells, probably conical ones, mainly occurring towards the base or along the major veins. These structures likely enhance the visual signalling in V. On a fresh flower, the UV yellow hue probably would be strong but as stated earlier this particular flower is a in a late withering stage so similar to what is seen with e.g. Potentilla anserina, the pigments causing the UV yellow false colour are leaked out. References:http://www.ultravioletphotography.com/content/index.php?/topic/88-common-literature-references/ [Published 23 June 2013] Link to comment
Nico Posted June 23, 2013 Share Posted June 23, 2013 Hi Bjørn,I’ve photographed Lathyrus pratensis near Bensheim, Germany on 14 June. The UV-image suffers from motion blur (taken in the field), so it was not on the list of species that I wanted to publish here. However, the flower that I have recorded is pretty UV-dark and doesn’t show any false-yellow. I will try another sample as soon as I get to it.Best regards,Nico Both images taken with my broadband G1 and the EL-Nikkor 80/f5.6 Visual light image (with IR-neutralisation filter) UV image (with Baader U-filter) Link to comment
nfoto Posted June 23, 2013 Author Share Posted June 23, 2013 I think we will see such discrepancies here and there as our coverage of species widens. Maybe there are underlying taxonomic issues, or differences causes by technique? Whatever the explanation, at present we can scarcely do more than collect more data and report irregularites when such are encountered. I checked some old UV captures of L. pratensis and they were pretty much similar to what I showed in the first post. Link to comment
nfoto Posted June 23, 2013 Author Share Posted June 23, 2013 This is from my old files, taken with Nikon D1H, UV-Nikkor 105 lens, and SB-140 flash. According to archived notes the filter was Hoya U-360, so some IR contamination is to be expected. I converted the image to b/w and increased contrast somewhat as a counter-measure. Material collected in the same location as in 2013. The same overall UV patterning is evident in this old capture. Also evidenced is the huge leap forward in UV image quality we have witnessed over the last decade. As to the image posted by Nico (German material UV) I think the contrast is very low and the overall image is underexposed, so it is really hard to tell if it is significantly different from the Norwegian samples shown here. In particular, one does observe the darkening pattern of the corolla wings. Link to comment
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