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[Andrea B.]

Blum, A.G. (2016) Persicaria maculosa S.F. Gray (Polygonaceae) Lady's Thumb. Leaves photographed in ultraviolet and visible light. http://www.ultraviol...sa-ladys-thumb/

Shore Cottage, Southwest Harbor, Maine, USA
01 August 2016
Wildflower

Synonyms:

• Lady's Thumb Smartweed
  
• Persicaria persicaria (L.) Small
  
• Persicaria vulgaris Webb & Moq.
  
• Polygonum dubium Stein
  
• Polygonum persicaria L.

Comment:
The central area on the P. maculosa leaf probably lacks chlorophyll so the anthocyanin shows through as a dark blotch. I was particularly interested in how this blotch would appear in UV light. As it turned out, the leaf blotch does not show up at all under my broadband BaaderU UV-pass filter. The flower spike had not yet fully bloomed before I had to leave Maine, so a more detailed UV-signature will have to wait until later.
The leaves are edible, but this introduced plant, native to Europe and Asia, is mostly regarded as a weed in the US. Although its pink flower spikes are pretty and gracefully arched, the plant can be a bit agressive if given a place in the garden.

Reference:
1. New England Wild Flower Society (2016) Persicaria maculosa. Lady's Thumb Smartweed. https://gobotany.new...caria/maculosa/


Equipment [Nikon D600-broadband + Nikon 105mm f/4.5 UV-Nikkor]

Visible Light [f/16 for 1/200" @ ISO-400 with Onboard Flash and Baader UVIR-Block Filter]
Dark leaf blotch.



Ultraviolet Light [f/8 for 15" @ ISO-200 with SB-14 UV-modified Flash and BaaderU UV-Pass Filter]
No sign of the leaf blotch in UV.



Ultraviolet Light [f/11 for 13" @ ISO-200 with SB-14 UV-modified Flash and BaaderU UV-Pass Filter]
The tiny pink flowers are mostly UV-dark.