Andrea B. Posted July 8, 2014 Share Posted July 8, 2014 Blum, A.G. (2014) Pilosella caespitosa (Dumort.) P.D. Sell & C. West (Asteraceae) Field Hawkweed. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...field-hawkweed/ Southwest Harbor, Maine, USA07 July 2014Wildflower Synonyms:Hieracium caespitosum DumortHieracium pratense TauschKing DevilYellow King DevilYellow HawkweedComments:The tightly clustered capitula of P. caespitosa provides for an easy identification of this plant. Field Hawkweed's UV appearance differs considerably from the other Pilosella we have photographed so far in that it has only a very small central UV-dark area while the rays are quite UV-bright. We had initially thought that the almost uniformly UV-dark appearance seen in Pilosella peleteriana and Pilosella aurantiaca might indicate another way of separating Pilosella from Hieracium, but clearly that UV-dark signature does not appear across all Pilosella species. References:1. New England Wild Flower Society (2014) Hieracium caespitosum. Yellow Hawkweed. https://gobotany.newenglandwild.org/species/hieracium/caespitosum/ Equipment [Nikon D600-broadband + Nikon 105mm f/4.5 UV-Nikkor] Visible Light [f/32 for 1/25" @ ISO 100 in Sunlight with Baader UVIR-Block Filter] Visible Light [f/22 for 1/15" @ ISO 100 in Sunlight with Baader UVIR-Block Filter] Visible Light [f/11 for 1/20" @ ISO 100 with onboard Flash and Baader UVIR-Block Filter]Aphids and a spittle bug nymph inside the white bubbly spittle (to the right) enjoy the flower. Ultraviolet Light [f/16 for 1/30" @ ISO 400 with SB-14 UV-modified Flash and Baader UV-Pass Filter]Stigmas are UV-dark. Ultraviolet Light [f/16 for 1/30" @ ISO 400 with SB-14 UV-modified Flash and Baader UV-Pass Filter]Unopened rays are UV-dark. Ultraviolet Light [f/11 for 1/30" @ ISO 400 with SB-14 UV-modified Flash and Baader UV-Pass Filter]UV-dark aphids and UV-white spittlebug spittle. Link to comment
Andrea B. Posted July 22, 2015 Author Share Posted July 22, 2015 SET 2Shore Cottage, Southwest Harbor, Maine, USA22 July 2015Wildflower Equipment [Nikon D600-broadband + Nikon 105mm f/4.5 UV-Nikkor] Visible Light [f/11 for 1/200" @ ISO-200 in Sunlight with Baader UVIR-Block Filter] Ultraviolet Light [f/11 for 1/2" @ ISO-200 in Sunlight with BaaderU UV-Pass Filter] Ultraviolet Light [f/11 for 1" @ ISO-200 in Sunlight with CopperU UV-Pass Filter] Simulated Bee Vision [f/11 for 1/10" @ ISO-200 in Sunlight with UG5 + S8612 Stack]The yellow, UV-absorbing areas of the rays would probably stimulate the bee's green receptor.With this filter stack, these areas are the darker green in this photo.The yellow, UV-reflecting areas would stimulate both the bee's green and UV receptors.With this filter stack, these areas are the lighter green yellow in this photo. Infrared Light [f/11 for 1/60" @ ISO-200 in Sunlight with B+W 093 IR-Pass Filter] Link to comment
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