Andrea B. Posted December 18, 2012 Share Posted December 18, 2012 Blum, A. G. (2012) Sonchus oleraceus L. (Asteraceae) Annual Sow-thistle. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...chus-oleraceus/ Primary Pigment: Carotenoids Other Common Names: Common Sow-thistle Smooth Sow-thistle Comment: The S. oleraceus flower in ultraviolet has a diffuse dark center with UV-black stamens. The ray florets become gradually brighter from center to periphery. The pollen appears to be UV-bright. This Sonchus is one of those few flowers which shows some IR-absorbing parts - on its stamens and phyllaries. S. oleraceus in Maine typically is glabrous on peduncles and phyllaries, only occasionally showing a few stipitate glands. Reference: 1. Mittelhauser et al. (2010) Annual Sow-thistle, page 113. The Plants of Acadia National Park. The U. of Maine Press, Orono, ME. Set 1 Death Valley National Park, Furnace Creek Ranch, Furnace Creek, California, USA 29 February 2012 (Leapday) Wildflower Equipment [Nikon D300-broadband + Nikon 105mm f/4.5 UV-Nikkor] Visible Light [f/13 for 1/750" @ISO 800 with Nikon D3S] Sonchus oleraceus growing near the Furnace Creek Ranch. Visible Light [f/11 for 1/750" @ISO 800 with Nikon D3S] Ray florets exhibit an abaxial stripe. Visible Light [f/11 for 1/1500" @ISO 800 with Nikon D3S] The leaf has large, angled "ears", or auricles, which clasp the stem. Visible Light [f/11 for 1/320" @ISO 400 in Sunlight with Baader UVIR-Block Filter] Ultraviolet Light [f/11 for 1/250" @ISO 1600 in Sunlight + Baader UV-Pass Filter] Infrared Light [f/11 for 1/250" @ISO 400 in Sunlight + B+W 092 IR-Pass Filter] Set 2 Southwest Harbor, Maine, USA 14 July 2007 Wildflower Comment: This Sow-thistle was growing in a small strip of dirt between the side of the Southwest Cycle store building and the driveway next to it. I found it there several summers in a row until the driveway was re-paved and it got weed-whacked. I expect it will grow back. Equipment [Nikon D200-broadband + Nikon 105mm f/4.5 UV-Nikkor] Visible Light [f/16 for 1/90" @ ISO 200 in Sunlight with Baader UVIR-Block Filter] Ultraviolet Light [f/16 for 4" @ ISO 200 in Sunlight + Baader UV-Pass Filter] Link to comment
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